Uplink control data transmission

ABSTRACT

Methods and systems for transmitting uplink control information and feedback are disclosed for carrier aggregation systems. A user equipment device may be configured to transmit uplink control information and other feedback for several downlink component carriers using one or more uplink component carriers. The user equipment device may be configured to transmit such data using a physical uplink control channel rather than a physical uplink shared channel. The user equipment device may be configured to determine the uplink control information and feedback data that is to be transmitted, the physical uplink control channel resources to be used to transmit the uplink control information and feedback data, and how the uplink control information and feedback data may be transmitted over the physical uplink control channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Non-Provisional applicationSer. No. 15/454,477, filed Mar. 9, 2017, which is a continuation of U.S.Non-Provisional application Ser. No. 15/268,838, filed Sep. 19, 2016,which is a continuation of U.S. Non-Provisional application Ser. No.12/895,900, filed Oct. 1, 2010, which issued as U.S. Pat. No. 9,485,060,on Nov. 1, 2016, which claims the benefit of U.S. ProvisionalApplication No. 61/247,679, filed Oct. 1, 2009, U.S. ProvisionalApplication No. 61/304,370, filed Feb. 12, 2010, U.S. ProvisionalApplication No. 61/320,172, filed Apr. 1, 2010, U.S. ProvisionalApplication No. 61/320,494, filed Apr. 2, 2010, U.S. ProvisionalApplication No. 61/329,743, filed Apr. 30, 2010, U.S. ProvisionalApplication No. 61/356,250, filed Jun. 18, 2010, U.S. ProvisionalApplication No. 61/356,316, filed Jun. 18, 2010, U.S. ProvisionalApplication No. 61/356,449, filed Jun. 18, 2010, U.S. ProvisionalApplication No. 61/356,281, filed Jun. 18, 2010, and U.S. ProvisionalApplication No. 61/373,706, filed Aug. 13, 2010, all of which are herebyincorporated by reference herein.

BACKGROUND

In order to support higher data rate and spectrum efficiency, the ThirdGeneration Partnership Project (3GPP) Long Term Evolution (LTE) systemhas been introduced into 3GPP Release 8 (R8). (LTE Release 8 may bereferred to herein as LTE R8 or R8-LTE.) In LTE, transmissions on theuplink are performed using Single Carrier Frequency Division MultipleAccess (SC-FDMA). In particular, the SC-FDMA used in the LTE uplink isbased on Discrete Fourier Transform Spread Orthogonal Frequency DivisionMultiplexing (DFT-S-OFDM) technology. As used hereafter, the termsSC-FDMA and DFT-S-OFDM are used interchangeably.

In LTE, a wireless transmit/receive unit (WTRU), alternatively referredto as a user equipment (UE), transmits on the uplink using only alimited, contiguous set of assigned sub-carriers in a Frequency DivisionMultiple Access (FDMA) arrangement. For example, if the overallOrthogonal Frequency Division Multiplexing (OFDM) signal or systembandwidth in the uplink is composed of useful sub-carriers numbered 1 to100, a first given WTRU may be assigned to transmit on sub-carriers1-12, a second WTRU may be assigned to transmit on sub-carriers 13-24,and so on. While the different WTRUs may each transmit into only asubset of the available transmission bandwidth, an evolved Node-B(eNodeB) serving the WTRUs may receive the composite uplink signalacross the entire transmission bandwidth.

LTE Advanced (which includes LTE Release 10 (R10) and may include futurereleases such as Release 11, also referred to herein as LTE-A, LTE R10,or R10-LTE) is an enhancement of the LTE standard that provides afully-compliant 4G upgrade path for LTE and 3G networks. In LTE-A,carrier aggregation is supported, and, unlike in LTE, multiple componentcarriers (CCs) may be assigned to the uplink, downlink, or both. Suchcarriers may be asymmetric (a different number of CCs may be assigned tothe uplink than the number of CCs assigned to the downlink.) Note thatCCs may also be known as cells, and in this disclosure the terms areused interchangeably.

In both LTE and LTE-A, there is a need to transmit certain associatedlayer 1/layer 2 (L1/2) uplink control information (UCI) to support theuplink (UL) transmission, downlink (DL) transmission, scheduling,multiple-input multiple-output (MIMO), etc. In LTE, if a WTRU has notbeen assigned an uplink resource for UL transmission of data (e.g., userdata), such as a Physical UL Shared Channel (PUSCH), then the L1/2 UCImay be transmitted in a UL resource specially assigned for UL L1/2control on a physical uplink control channel (PUCCH). What are needed inthe art are systems and methods for transmitting UCI and other controlsignaling utilizing the capabilities available in an LTE-A system,including carrier aggregation.

SUMMARY

Methods and systems for transmitting uplink control information (UCI)and other feedback data, in particular HARQ ACK/NACK, in wirelesscommunications system using carrier aggregation are disclosed. In anembodiment, a UE may be configured to determine the particularinformation bits that are to be transmitted as part of UCI or otherfeedback data. A UE may also be configured to determine the particularresources that may be used to transmit feedback when such transmissionis to be performed using PUCCH resources. A UE may also be configured todetermine how to transmit such feedback, for example, by determining theencoding to be used, the appropriate symbol mapping, the transmissionpower settings, and other aspects of feedback transmission.

More specifically, a UE may be configured to determine a codebook sizeand/or implement methods of reducing codebook size and/or states used ina codebook. A UE may also be configured to determine when a PDCCHreception is missed and/or detect a false positive PDCCH reception. A UEmay also be configured to determine the appropriate PUCCH resources forHARQ ACK/NACK feedback and where within PUCCH that such feedback is tobe located. A UE may also be configured to perform methods of bundlingACK/NACK on PUCCH. In an embodiment, a UE may be configured to determinestatic ACK/NACK resources. In a further embodiment, a UE may beconfigured to perform PUCCH resource selection using DL SPS. A UE mayalso be configured to use multiplexing with PUCCH for UCI and feedbackdata. A UE may also be configured to determine PUCCH resources using aCCE index.

In an embodiment, a UE may be configured to determine channel coding andphysical resource mapping for feedback, such as HARQ ACK/NACK. A UE mayalso be configured for multiplexing feedback data with feedback datafrom other UEs, and for simultaneously transmitting SRS with feedbackdata. In an embodiment, a UE may be configured to use extended cyclicprefix in transmitting feedback data. A UE may also be configured toaccount for unequal robustness when performing channel selection. A UEmay be configured to handle SR in various ways disclosed herein. A UEmay also be configured to determine transmit power when transmittingfeedback data using PUCCH. These and additional aspects of the currentdisclosure are set forth in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description of disclosed embodiments is betterunderstood when read in conjunction with the appended drawings. For thepurposes of illustration, there is shown in the drawings exemplaryembodiments; however, the subject matter is not limited to the specificelements and instrumentalities disclosed. In the drawings:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented.

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A.

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A.

FIG. 2 illustrates a non-limiting exemplary PUCCH configuration that maybe used in some systems and methods for transmitting uplink controldata.

FIG. 3 illustrates non-limiting exemplary carrier aggregationconfigurations that may be used by some methods and systems fortransmitting uplink control data.

FIG. 4 illustrates a non-limiting exemplary system for generating aPUCCH subframe in format 1 that may be used in some systems and methodsfor transmitting uplink control data.

FIG. 5 illustrates a non-limiting exemplary system for generating aPUCCH subframe in format 2 that may be used in some systems and methodsfor transmitting uplink control data.

FIG. 6 is a graphical representation of performance improvements thatmay be achieved using one or more embodiments disclosed herein.

FIG. 7 illustrates a non-limiting exemplary method for determining acodebook based on activated CCs according to an embodiment of thepresent disclosure.

FIG. 8 illustrates a non-limiting exemplary method of using a sequencenumber in an activation/deactivation command according an embodiment ofthe present disclosure.

FIG. 9 illustrates a non-limiting exemplary method of combining statesaccording an embodiment of the present disclosure.

FIG. 10 illustrates a non-limiting exemplary method of partiallycombining or grouping states according to an embodiment of the presentdisclosure.

FIG. 11 illustrates a non-limiting exemplary method of using stateprobabilities according an embodiment of the present disclosure.

FIG. 12 illustrates a non-limiting exemplary method of using partitionsaccording an embodiment of the present disclosure.

FIG. 13 illustrates a non-limiting exemplary method of using comparativeNACK quantities according an embodiment of the present disclosure.

FIG. 14 illustrates a non-limiting exemplary configuration usingtime-domain partial bundling with component carrier multiplexingaccording an embodiment of the present disclosure.

FIG. 15 illustrates a non-limiting exemplary configuration usingdownlink assignment indicators according an embodiment of the presentdisclosure.

FIG. 16 illustrates another non-limiting exemplary configuration usingdownlink assignment indicators according an embodiment of the presentdisclosure.

FIG. 17 illustrates a non-limiting exemplary configuration usingextended downlink indicators or extended downlink assignment indicatorsaccording an embodiment of the present disclosure.

FIG. 18 illustrates a non-limiting exemplary method of selecting a PUCCHallocation method according an embodiment of the present disclosure.

FIG. 19 illustrates a non-limiting exemplary PUCCH configuration thatmay be used in some systems and methods for transmitting uplink controldata.

FIG. 20 illustrates a non-limiting exemplary method of using generatingcontrol information and feeding control information back to a networkaccording an embodiment of the present disclosure.

FIG. 21 illustrates a non-limiting exemplary method encoding PUCCHaccording to an embodiment of the present disclosure.

FIG. 22 illustrates a non-limiting exemplary control signal mappingaccording to an embodiment of the present disclosure.

FIG. 23 illustrates a non-limiting exemplary shortened PUCCH structureaccording to an embodiment of the present disclosure.

FIG. 24 illustrates another non-limiting exemplary shortened PUCCHstructure according to an embodiment of the present disclosure.

FIG. 25 illustrates a non-limiting exemplary feedback transmissionstructure according to an embodiment of the present disclosure.

FIG. 26 illustrates a non-limiting exemplary feedback transmissionstructure according to an embodiment of the present disclosure.

FIG. 27 illustrates a non-limiting exemplary PUCCH structure accordingto an embodiment of the present disclosure.

FIG. 28 illustrates a non-limiting exemplary PUCCH structure accordingto an embodiment of the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the networks 112. By way of example, the base stations 114 a, 114b may be a base transceiver station (BTS), a Node-B, an eNodeB, a HomeNode B, a Home eNodeB, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it will be appreciated that the basestations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNodeB, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it will be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It will be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 104 and the core network 106according to an embodiment. As noted above, the RAN 104 may employ anE-UTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102c over the air interface 116. The RAN 104 may also be in communicationwith the core network 106.

The RAN 104 may include eNodeBs 140 a, 140 b, 140 c, though it will beappreciated that the RAN 104 may include any number of eNodeBs whileremaining consistent with an embodiment. The eNodeBs 140 a, 140 b, 140 cmay each include one or more transceivers for communicating with theWTRUs 102 a, 102 b, 102 c over the air interface 116. In one embodiment,the eNodeBs 140 a, 140 b, 140 c may implement MIMO technology. Thus, theeNodeB 140 a, for example, may use multiple antennas to transmitwireless signals to, and receive wireless signals from, the WTRU 102 a.

Each of the eNodeBs 140 a, 140 b, 140 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1C, theeNodeBs 140 a, 140 b, 140 c may communicate with one another over an X2interface.

The core network 106 shown in FIG. 1C may include a mobility managementgateway (MME) 142, a serving gateway 144, and a packet data network(PDN) gateway 146. While each of the foregoing elements are depicted aspart of the core network 106, it will be appreciated that any one ofthese elements may be owned and/or operated by an entity other than thecore network operator.

The MME 142 may be connected to each of the eNodeBs 142 a, 142 b, 142 cin the RAN 104 via an Si interface and may serve as a control node. Forexample, the MME 142 may be responsible for authenticating users of theWTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selecting aparticular serving gateway during an initial attach of the WTRUs 102 a,102 b, 102 c, and the like. The MME 142 may also provide a control planefunction for switching between the RAN 104 and other RANs (not shown)that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 144 may be connected to each of the eNode Bs 140 a,140 b, 140 c in the RAN 104 via the Si interface. The serving gateway144 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 144 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 144 may also be connected to the PDN gateway 146,which may provide the WTRUs 102 a, 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 106 may facilitate communications with other networks.For example, the core network 106 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices. For example, the corenetwork 106 may include, or may communicate with, an IP gateway (e.g.,an IP multimedia subsystem (IMS) server) that serves as an interfacebetween the core network 106 and the PSTN 108. In addition, the corenetwork 106 may provide the WTRUs 102 a, 102 b, 102 c with access to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

In an embodiment, WTRUs (referred to also as “UEs” herein) may transmittheir data (e.g., user data) and in some cases their control informationon the physical downlink shared channel (PDSCH). The transmission of thePDSCH may be scheduled and controlled by a base station (e.g., aneNodeB) using a downlink scheduling assignment that may be carried onphysical downlink control channel (PDCCH). As part of the downlinkscheduling assignment, the UE may receive control information on themodulation and coding set (MCS), downlink resources allocation (i.e.,the indices of allocated resource blocks), etc. Then, if a schedulingassignment is received, the UE may decode its allocated PDSCH resourceson the correspondingly allocated downlink resources.

In such embodiments, for the uplink (UL) direction, there may also be aneed for certain associated Layer 1/Layer 2 (L1/L2) control signaling(such as ACK/NACK, CQI, PMI, RI, etc.) to support the UL transmission,DL transmission, scheduling, MIMO, etc. If a UE has not been assigned anuplink resource for UL data transmission (e.g., a PUSCH) then the L1/L2uplink control information may be transmitted in a UL resource speciallyassigned for UL L1/L2 control on the Physical Uplink Control Channel(PUCCH). These PUCCH resources are located at the edges of the totalavailable cell BW. The control signaling information carried on thePUCCH may include scheduling requests (SRs), HARQ ACK/NACK transmittedin response to downlink data packets on the Physical Downlink SharedChannel (PDSCH), and channel quality information (CQI), and any othertype of UCI or feedback data.

PUCCH may support a variety different formats that may be chosendepending on the information to be signaled, such as format 1/1a/1b andformat 2/2a/2b. PUCCH may be a shared frequency/time resource reservedfor a UE to transmit any necessary control signaling. Each PUCCH regionmay be designed such that control signaling transmitted from a largenumber of UEs simultaneously with a relatively small number of controlsignaling bits per UE may be multiplexed into a single resource block(RB). The total number of RBs available for PUCCH transmission within acell may be specified by the higher layer parameter N_(RB) ^(HO). TheseRBs may then be split and allocated for PUCCH format 1/1a/1b and PUCCHformat 2/2a/2b transmissions. In systems where small system bandwidthssuch as 1.4 MHz are used, in an embodiment, a mixed format RB thatallows PUCCH format 1/1a/1b and format 2/2a/2b to share the same RB maybe implemented. In such an embodiment, the mixed format RB is configuredby the higher layer parameter N_(CS) ⁽¹⁾ that may specify the number ofreserved resources for PUCCH format 1/1a/1b within a mixed format RB. Insome embodiments, there may be no mixed format RB present if N_(CS)⁽¹⁾=0. With respect to PUCCH format 2/2a/2b, the number of reserved RBsmay be configured by a higher-layer parameter, such as N_(RB) ⁽²⁾. Theresources used for the transmission of PUCCH format 1/1a/1b and format2/2a/2b may be identified by the indices n_(PUCCH) ⁽¹⁾ and n_(PUCCH) ⁽²⁾respectively.

With respect to PUCCH format 1/1a/1b, the resources may be used for bothpersistent and dynamic ACK/NACK signaling. The dynamic format 1/1a/1bresources may be defined for the support of dynamically-scheduleddownlink data transmissions. The number of reserved resources forpersistent HARQ ACK/NACK and/or SR transmissions in uplink may beconfigured by a higher-layer parameter, such as N_(PUCCH) ⁽¹⁾, and thecorresponding allocation may be determined through higher layersignaling. Allocation of the dynamic PUCCH format 1/1a/1b resource maybe made implicitly according to the PDCCH allocation. In an embodiment,there may be a one-to-one mapping between each dynamic PUCCH format1/1a/1b resource and the lowest CCE index of the PDCCH transmission.Implicit allocation of the PUCCH format 1/1a/1b may lower the controlsignaling overhead. The implicit mapping for dynamic ACK/NACK resourceallocation may be defined as:n _(PUCCH) ⁽¹⁾ =n _(CCE) +N _(PUCCH) ⁽¹⁾where n_(CCE) may be the index of the first CCE used for transmission ofthe corresponding DCI assignment and N_(PUCCH) ⁽¹⁾ may be the number ofresources reserved for persistent PUCCH Format 1/1a/1b ACK/NACKsignaling.

FIG. 2 illustrates an exemplary PUCCH configuration that may be used insome embodiments, including those that operate in an LTE R8 environment.RBs 210 may be the RBs reserved for the PUCCH as configured by N_(RB)^(HO). Among RBs 210, RBs 220 may be reserved for PUCCH format 2/2a/2bas configured by N_(RB) ⁽²⁾. Also among RBs 210, RB 230 may be a mixedRB that may be used for both PUCCH format 1/1a/1b and format 1/2a/2b, asmay be configured by N_(CS) ⁽¹⁾. Further among RBs 210, RBs 240 may beresources that may be reserved for persistent PUCCH format 1/1a/1b asconfigured by N_(PUCCH) ⁽¹⁾. Also among RBs 210, RBs 250 may beresources reserved for dynamic PUCCH format 1/1a/1b. In an embodiment,for PUCCH format 1/1a/1b the resource index n_(PUCCH) ⁽¹⁾ may determinethe orthogonal sequence index and/or the corresponding value of thecyclic shift within each RB.

As noted above, in LTE-A, bandwidth extension, also known as carrieraggregation, may be used to achieve higher rates of data transmission.Bandwidth extension may allow both downlink (DL) and uplink (UL)transmission bandwidths to exceed 20 MHz and may allow for more flexibleusage of the available paired spectrum. For example, whereas LTE R8 maybe limited to operate in symmetrical and paired frequency-divisionduplexing (FDD) mode, LTE-A may be configured to operate in asymmetricconfigurations (e.g., having more component carriers (CCs) in thedownlink than the uplink or vice versa). Three different configurationsfor LTE-A carrier aggregation are illustrated in FIG. 3. Inconfiguration 310, symmetric carrier aggregation is illustrated, wherethere are the same number of component carriers used for both UL and DL.Configuration 320 illustrates the use of more DL component carriers thanUL component carriers. In the illustrated example, two componentcarriers for DL are shown and one for UL. In configuration 330, theopposite scenario is shown, with two component carriers in used for ULand one for DL. Any other combination and number of component carriersfor UL and DL are contemplated as within the scope of the presentdisclosure.

In an embodiment, a UE may be configured to received data over multipleDL CCs or serving cells, utilizing bandwidth extension, also known ascarrier aggregation, to achieve higher rates of data transmission.Therefore, such a UE may also need to transmit UCI or other feedback forthe several DL CCs via one or more UL CCs. When a UE has user data totransmit or has otherwise been assigned an UL resource for transmissionof data, such as a Physical UL Shared Channel (PUSCH), then the UE maytransmit UCI and feedback data using the assigned PUSCH. However, when aUE has not been assigned a PUSCH, the UE may be configured to transmitUCI and/or UL feedback data in a UL resource specially assigned for ULcontrol on a physical uplink control channel (PUCCH). Present herein arevarious systems, means, and methods for determining the UCI and feedbackdata that may be transmitted, determining the PUCCH resources to be usedto transmit such UCI and feedback data, and determining how such UCI andfeedback data may be transmitted over PUCCH.

In embodiments that utilize PUCCH transmission methods for transmittingUCI, including hybrid automatic repeat request (HARQ) acknowledgements(ACK) and negative acknowledgements (NACK) (referred to as “HARQACK/NACK” or simply “ACK/NACK” herein), either of PUCCH format 1/1a/1band PUCCH format 2/2a/2b may be used for such transmissions. While bothformats may be used to transmit UCI such as channel quality information(CQI), precoding matrix indication (PMI), rank indication (RI),ACK/NACK, etc., some embodiments may be configured to transmit CQI, PMI,and RI using PUCCH format 2/2a/2b and HARQ ACK/NACK using format1/1a/1b.

The two formats, PUCCH format 1/1a/1b and PUCCH format 2/2a/2b (whichmay be referred to herein as simply “format 1” and “format 2”,respectively), may be distinguished by whether channel coding (e.g.,Reed Muller coding) is used or not and whether time domain spreading isused or not, and the number of demodulation reference signals (DMRS).PUCCH format 2/2a/2b may use channel coding and no time domainspreading, whereas PUCCH format 1/1a/1b may use time domain spreadingwithout channel coding. PUCCH format 1, as illustrated in FIG. 4 showingnon-limiting exemplary PUCCH structure 400, is different from PUCCHformat 2, as illustrated in FIG. 5 showing non-limiting exemplary PUCCHstructure 500, in terms of channel coding and DMRS symbols. Thesefigures illustrate one timeslot in a subframe for a normal cyclic prefix(CP) case. As may be seen in FIG. 4, in PUCCH format 1, three DMRSs areused (DMRSs 410, 420, and 430) while in PUCCH format 2, as seen in FIG.5, two DMRSs are used (DMRSs 510 and 520.) Also as may be seen in thesefigures, the positions within the subframe of the DMRSs are different ineach format. In format 1, DMRSs 410, 420, and 430 are configured at longblocks (LBs) 3, 4, and 5, respectively, while in format 2, DMRSs 510 and520 are configured at LB 1 and LB 5, respectively.

In an embodiment, HARQ ACK/NACKs may be transmitted in PUCCH. Anycombination of UCI including HARQ ACK/NACK on PUCCH may be used,including HARQ-ACK using PUCCH format 1a or 1b, HARQ-ACK using PUCCHformat 1b with channel selection, scheduling request (SR) using PUCCHformat 1, HARQ-ACK and SR using PUCCH format 1a or 1b, CQI using PUCCHformat 2, and/or CQI and HARQ-ACK using PUCCH format 2a or 2b for normalcyclic prefix, and PUCCH format 2 for extended cyclic prefix

In embodiments that employ carrier aggregation (CA) (alternativelyreferred to as bandwidth extension herein), a UE may simultaneouslytransmit over the PUSCH and receive over the PDSCH of multiple CCs. Insome implementations, up to five CCs in the UL and in the DL may besupported, allowing flexible bandwidth assignments up to 100 MHz. Thecontrol information for the scheduling of PDSCH and PUSCH may be sent onone or more PDCCH(s). Scheduling may be performed using one PDCCH for apair of UL and DL carriers. Alternatively, cross-carrier scheduling mayalso be supported for a given PDCCH, allowing a network to provide PDSCHassignments and/or PUSCH grants for transmissions in other CC(s).

In an embodiment, a primary component carrier (PCC) may be used. A PCCmay be a carrier of a UE configured to operate with multiple componentcarriers for which some functionality (for example, derivation ofsecurity parameters and NAS information) may be applicable only to thatcomponent carrier. The UE may be configured with one or more PCCs forthe downlink (DL PCC). In such embodiments, a carrier that is not a PCCof the UE may be referred to as a secondary component carrier (SCC).

The DL PCC may correspond to the CC used by the UE to derive initialsecurity parameters when initially accessing a system. However, a DL PCCmay not be limited to this function. A DL PCC may also serve as the CCthat contains any other parameters or information for system operation.In an embodiment, a system may be configured such that a DL PCC cannotbe deactivated.

In carrier aggregation embodiments, multiple ACK/NACKs for multiple DLcarriers with either single or double codewords may be transmitted.Several PUCCH ACK/NACK transmission methods for HARQ ACK/NACKs incarrier aggregation may be used. Included among these are PUCCH JointCoding where multiple ACK/NACKs may be jointly encoded and transmittedin PUCCH. Different PUCCH formats may be used to transmit ACK/NACKs suchas PUCCH format 2 as shown in FIG. 3 and an alternative format, such asa DFT-S-OFDM format. Another transmission method may be spreading factor(SF) reduction, where the time domain orthogonal spreading may beremoved (no spreading) or reduced to length two (SF=2) as opposed tolength four (SF=4). This may enable a UE to carry more ACK/NACK bitsusing a single cyclic shift. Another transmission method may be channelselection (CS), where, similar to a TDD ACK/NACK multiplexingtransmission scheme using PUCCH format 1b. Another transmission methodmay be multi-code transmission (NxPUCCH) where multiple codes may beassigned to a single UE to transmit multiple ACK/NACKs, as opposed to asingle code. Any, all, or any combination of these methods may be used,and all such embodiments are contemplated as within the scope of thepresent disclosure.

In some LTE and/or LTE-A implementations, simultaneous ACK/NACK on PUCCHtransmission from one UE on multiple UL CCs may not be supported, and asingle UE-specific UL CC may be configured semi-statically for carryingPUCCH ACK/NACK.

In order to provide ACK/NACK feedback, for example in LTE-A systems,PUCCH joint coding may be used to transmit multiple HARQ ACK/NACKs.However, PUCCH joint coding may result in high coding rate and lowcoding gain. Therefore, a design tradeoff may be required to balancethese effects. In an embodiment, state reduction methods may be used toaddress this tradeoff. State reduction methods may reduce the number ofstates required for the transmission of ACK/NACK and/or discontinuoustransmission data (DTX), and/or may reduce the number of bits requiredfor the transmission.

By reducing the size of the ACK/NACK/DTX codebook, fewer bits may needto be transmitted. This may be accomplished, in an embodiment, byfeeding back a codebook index or indicating “scheduled CCs (or servingcells)” instead of “activated CCs (or serving cells)” or “configured CCs(or serving cells)”, either from a network node (e.g., an eNodeB) to aUE or from a UE to a network node. Reduced ACK/NACK and DTX states mayresult in fewer bits for representing the states. For a given codebook,states may be further reduced by considering different requirements forprimary serving cells and secondary serving cells, state combining,grouping, bundling, special rules for codebook construction, etc. Thus,state reduction may be the result of efficient utilization of a codebookrather than designing a specific codebook.

The embodiments described herein may be used with PUCCH joint codingusing PUCCH format 1/1a/1b, joint coding using PUCCH format 2/2a/2b,and/or joint coding using an alternative format, such as a blockspreading based format or a DFT-S-OFDM-based format. Set forth below areembodiments for PUCCH joint coding methods and joint coding performanceenhancements. Systems, means, and methods for ACK/NACK/DTX codebook sizereduction and ACK/NACK/DTX state reduction will be disclosed, as well ascoding for a codebook and some codebook designs for HARQ ACK/NACK. Thedescribed enhancements to PUCCH joint coding may provide improved jointcoding gain and a lower effective joint coding rate. The embodimentsdescribed herein may also provide efficient ACK/NACK/DTX methods forsignaling and determining when and how the codebook may be applied, etc.

In an embodiment that may be used for reducing the ACK/NACK/DTX codebooksize, codebook size reduction may be achieved using a signaling-basedapproach. In such an embodiment, actual scheduled CCs (k carriers) maybe signaled in a downlink. Alternatively, a codebook index may besignaled in an uplink.

In an embodiment, an ACK/NACK/DTX codebook may be determined based onthe actual CCs that are scheduled (k). Alternatively, the ACK/NACK/DTXcodebook may be determined by the last CC whose PDCCH is detected. Theactual CCs k that are scheduled may be signaled to a UE, while thecodebook index whose PDCCH is lastly detected may be signaled to a basestation (e.g., an eNodeB.)

If the codebook is to be determined by actual scheduled CCs k ratherthan the activated or configured CCs (M), the total number of states(i.e., codebook size) may be reduced to 3^(k)−1 states from 3^(M)−1. ForM=5 and k=2, the codebook size may be reduced to 8 from 242. Therequired number of bits for representing the codebook is thus reduced to2 bits from 8 bits. The coding rate may be improved to 0.1 from 0.36accordingly. The performance improvement up to a couple of dB that maybe achievable is illustrated in FIG. 6.

A UE may need to know how many and which CCs are scheduled by a basestation (e.g., an eNodeB) in order to determine the codebook andcode-point in the codebook. To determine the right codebook andcode-point may require knowledge of the number of CCs that are scheduledand the exact CCs are scheduled. Upon determining the number of CCsbeing scheduled, the UE may determine the codebook or the codebook size.Upon determining the exact CCs that are being scheduled (in anembodiment, using the corresponding PDCCH/PDSCH detection result), theUE may determine the exact code-point in the codebook.

In an embodiment, this may be accomplished by signaling a bitmap in adynamic manner to indicate how many and which CCs are scheduled. Thismay require a few bits (e.g., 5 bits bitmap where five CCs areconfigured or activated.) These bits may be inserted in downlink controlinformation (DCI) for DL assignment. Alternatively, an order forscheduled CCs may be used such that once the number of CCs that arescheduled is known, exactly which CCs are being scheduled may also beknown automatically or implicitly. This embodiment may reduce the numberof bits required to be signaled (e.g., 2 bits) to indicate both how manyand exactly which CCs are being scheduled. This embodiment may beimplemented by signaling to a UE from a base station (e.g., an eNodeB)or signaling to a base station from UE. When signaling to a UE from abase station is used, the signaling may include the number of CCs thatare scheduled to WTRU. When signaling to a base station from a UE isused, the signaling may include transmitting the codebook index to thebase station. Such an index may be derived based on the last CC whosePDCCH is detected.

In embodiments where signaling is performed from a base station (e.g.,an eNodeB) to a UE, the codebook may be determined based on thescheduled CCs (rather than the activated CCs.) Configured or activatedCCs may be ranked in order and CCs may be scheduled based on the order.The order may be based on channel quality, CC index, CC priority,frequency index, logic channel prioritization (LCP) for CCs, or anyother criteria. The first in order may be designated as the PCC, withthe following CCs designated secondary CCs (e.g., PCC, secondary CC1,CC2, etc.) This ordering may impose some restriction on CC scheduling.

In such embodiments, an indicator in DCI may provide information aboutscheduled CCs. In Table 1 below, illustrating an example implementationof such an embodiment (Example A), 2-bit indicators that can support upto four scheduled CCs are shown. Example A may provide an ACK/NACK/DTXcodebook size as small as 2 (where the minimum codebook is a 1-bitcodebook).

TABLE 1 Example A - 2-bit indicators for up to four CCs Number ofscheduled CCs (k) Indicator Only PCC 00 PCC + SCC1 01 PCC + SCC1, SCC210 PCC + SCC1, SCC2, SCC3 11

Table 2 illustrates another example implementation of such an embodiment(Example B) where a 2-bit indicator that can support up to fivescheduled CCs (2 bits) is used. Example B may provide ACK/NACK/DTXcodebook size as small as 8 (where a minimum codebook is a 3-bitcodebook). Note that in other embodiments, more than 2 bits may be used(e.g., 3 bits or more) to indicate other ranking or combinations of CCs.

TABLE 2 Example B - 2-bit indicators for up to five CCs Codebook size(based on number of scheduled CCs (k)) Indicator Codebook size 2 (PCC +SCC1) 00 Codebook size 3 (PCC + SCC1, 01 SCC2) Codebook size 4 (PCC +SCC1, 10 SCC2, SCC3) Codebook size 5 (PCC + SCC1, 11 SCC2, SCC3, SCC4)

In embodiments where signaling may be performed from a UE to a basestation (e.g., an eNodeB), the UE may detect the PDCCH for CCs that areactivated. The activated or configured CCs may be ordered as describedabove. If the last CC whose PDCCH is detected is CC#j, since CCs may bescheduled in order, those CCs before the last detected CC or CC#j (i.e.,CC#i, i=1, 2, . . . , i<j) may also be scheduled in the same subframe.The codebook or codebook size may be determined based on the number j.The codebook size may be 3^(j)−1. The codebook of the size 3^(j)−1 maybe selected. The codebook index corresponding to the selected codebookmay be signaled to the base station. The codebook index mapping tocodebook or codebook size may have following property: codebook #1 hasone CC, codebook #2 has 2 CCs, codebook #3 has 3 CCs, codebook #1 has jCCs.

The codebook index j may be signaled to a base station (e.g., aneNodeB). Since the base station may know for which CCs it has PDCCHscheduled, it therefore may know which CCs whose PDCCHs are not detectedby a UE when receiving the codebook index fed back from the UE. Thus thebase station may know exactly how to handle the DTX. This may occur ifthe last CC is not the “true” last CC because of a PDCCH miss detectionby UE, that is, if CC#j+1, CC#j+2, etc. are also scheduled by the basestation but not detected by the UE. In this case, the base station mayknow that PDCCH for CC#j+1 is not detected by the UE although it isscheduled. The base station may know that the UE is in a DTX mode due tothe UE having missed the PDCCH.

Method 700 in FIG. 7 is one exemplary non-limiting method ofimplementing an embodiment where a codebook may be determined based onactivated CCs. In one such embodiment, method 700 may be implemented ata UE when the new codebook and activation/deactivation command areapplied. At block 710, a determination may be made as to whether anactivation/deactivation command has been successfully received. In anembodiment, such a command may be received in subframe n−4. If anactivation/deactivation command has been successfully received at block710, the UE may determine how many and which CCs are activated ordeactivated, in an embodiment based on the most recently receivedcommand in subframe n−4, at block 720. At block 730, the UE maydetermine a new codebook based on the newly activated/deactivated CCs.At block 740, the UE may transmit, in an embodiment in subframe n, bitsin PUCCH for the state containing ACK, NACK and DTX corresponding to CCreceiving activation command, in an embodiment in subframe n−4, usingthe previous codebook (i.e., the new codebook is not applied yet).

At block 750, the UE may apply the activation/deactivation command, inan embodiment in subframe n+4. At block 760, the UE may apply the newcodebook for ACK/NACK transmission responding to PDSCH received, in anembodiment in subframe n+4. At block 770, the UE may transmit bits forACK/NACK/DTX state in PUCCH using new codebook, in an embodiment insubframe n+8. Note that if, at block 710, it is determined that anactivation/deactivation command has not been successfully received, theUE may wait for retransmission of such a command at block 780.

In an embodiment, a sequence indicator or sequence number may be usedand inserted in an activation command to keep theactivation/deactivation commands in order when a sequence ofactivation/deactivation commands are sent and a detection error occurswhich causes the commands to be received out of order. Method 800 inFIG. 8 is an exemplary non-limiting method of implementing such anembodiment. At block 810, a UE may receive one of a plurality ofactivation/deactivation commands. At block 820, the UE may extract asequence indicator or sequence number from the activation/deactivationcommand. At block 830, the UE may determine whether the sequenceindicator or sequence number is the expected or correct number orindicator. In other words, the UE may determine whether the sequenceindicator or sequence number follows the next most recently receivedsequence indicator or sequence number. If the sequence indicator orsequence number is not the expected number or indicator, at block 840,the UE may reorder the activation/deactivation commands accordingly sothat they are processed in the order intended (i.e., in the ordertransmitted by the base station.) At block 850, the UE may process theactivation/deactivation commands in the proper order (i.e., according tothe sequence numbers or indicators.) If, at block 830, the UE determinesthat the expected sequence number was extracted at block 820, theactivation/deactivation commands may be processed in order at block 850without any reordering.

In an embodiment, systems, methods, and means for reducing the number ofACK/NACK/DTX states may be used. In a state subspace-based approach,ACK/NACK/DTX state space may be partitioned into several segments orpartitions. Each segment or partition may contain a smaller number ofstates upon which the generation of a codebook may be based. Eachsegment or partition (which may also be referred to as a “subspace”herein) may be a codebook. States of each subspace may be representedwith a fewer number of bits in the corresponding state subspace (i.e.,each code-point may be represented with a smaller number of bits.)Partitioning the state space may improve the joint coding gain and/orlower the effective joint coding rate for PUCCH joint coding. Based onthe PDCCH/PDSCH detection outcome at a UE, an ACK/NACK/DTX state may begenerated. The state segment or partition that contains this generatedACK/NACK/DTX state may be selected. The generated state may be mapped toa code-point in the corresponding codebook for the segment or partition.

In order to inform a base station (e.g., an eNodeB) of the state segmentor partition the UE has selected, the UE may be configured to perform aresource-based method. In an embodiment, two or more PUCCH resources maybe configured or reserved either explicitly or implicitly (e.g., byPDCCH CCE address) corresponding to state segments or partitions. The UEmay generate ACK, NACK, and/or DTX for CCs based on the outcome of thePDCCH/PDSCH detection. The UE may determine the ACK/NACK/DTX state,encode the state information bits using the corresponding RM coding forthe segment containing this state, and transmit the encoded bits of thisstate. The base station may obtain the knowledge of which state segmentor partition has been selected by the UE by detecting which PUCCHresource is used. This may be based on techniques such as correlationdetection or energy detection. Table 3 provides an example of mappingthe PUCCH resource index to a segment or partition. The base station maydecode the received PUCCH using a Reed Muller (RM) code for thissegment.

TABLE 3 Example PUCCH resource index to segment/partition mapping PUCCHResource State subspace Resource index#x Segment (subspace) A Resourceindex#y Segment (subspace) B Resource index#z Segment (subspace) C

In an embodiment, a UE may be configured to perform a mask orinterleaving pattern based method. In this embodiment, different masksor interleaving patterns for PUCCH may be used by a UE for differentsegment or partition of states. Similarly, a base station (e.g., aneNodeB) may obtain knowledge of which state segment or partition hasbeen selected by the UE by detecting which PUCCH mask or interleavingpattern is used. This may be based on techniques such as correlationdetection. Table 4 provides an example of mapping the PUCCH mask indexor interleaving pattern to a segment or partition.

TABLE 4 Example PUCCH mask index/interleaving pattern tosegment/partition mapping PUCCH Masking/Interleaving State subspaceMask#x or interleaving pattern x Segment (subspace) A Mask#y orinterleaving pattern y Segment (subspace) B Mask#z or interleavingpattern z Segment (subspace) C

For example, let there be three masks denoted as M1, M2 and M3, where Gis an RM encoder and s is an information bit vector. In this example,x=Gs. If Mj is the mask used at a transmitter, the received signal isy=Mj*x+n where n is the noise. The receiver may search the correct maskand the corresponding segment or partition using the following costfunction:

${cost} = {\arg\limits_{{Mi},{i = 1},2,3,s}\min{{y - {MiGs}}}^{2}}$

In an example of such an embodiment, for four CCs it may require 80states in total which in turn requires seven bits for representing thestates. States may be partitioned into three subspaces, segments 1, 2,and 3, where each segment contains 26 or 27 states (five bits). A ReedMuller coding (20, 5) may be used for encoding information bits (forstates) in each segment. The effective coding rate may be reduced orimproved to 0.25 from 0.35, thus the coding gain may be significantlyincreased. The more subspaces or segments into which the entire statespace is partitioned, the lower the coding rate may be and the betterthe joint coding gain may be.

In an embodiment, systems, methods, and means for combining or groupingACK/NACK/DTX states may be used. In order to improve the PUCCH jointcoding gain and lower the effective joint coding rate, ACK/NACK/DTXstates may be combined into fewer states and thus fewer bits may berequired to represent the states. For example, a NACK and a DTX may becombined into a single state identified as “NACK/DTX”. The total numberof states may be reduced from 3^(M) states to 2^(M) states. Thecorresponding required bits for representing the states may be reducedfrom log₂(3^(M)) bits to log₂(2^(M)) bits. For example, for M=5, thenumber of states may be reduced to 32 from 243, the number of bits maybe reduced to 5 bits from 8 bits, and the coding rate may be improved to0.22 from 0.36. FIG. 6 illustrates performance improvements in anexemplary system due to this reduction in the number of states due tostate combining.

A number of methods and means may be employed for state combining. In anembodiment, PCC and SCCs may be used. The PCC may have betterperformance than the SCC since PCC since it may carry certain “critical”signaling or information. Method 900 of FIG. 9 is an exemplarynon-limiting method of implementing such an embodiment. In thisembodiment, the NACK and DTX states may be distinguished for a PCC, butmay not be distinguished for an SCC. At block 910, a determination maybe made as to whether a PDCCH is detected for a CC. If there is no PDCCHdetected for a CC, then at block 920, a determination may be made as towhether the CC is a PCC or a SCC. If the CC is a PCC, at block 930 theUE may indicate “DTX” for the CC. If the CC is a SCC, at block 940 theUE may indicate “NACK/DTX” for the CC.

If, at block 910, the UE determines that a PDCCH is detected for a CC,at block 950 the UE may determine whether a PDSCH is receivedsuccessfully for the CC. If a PDSCH is successfully received for the CC,at block 960 the UE may indicate “ACK” for the CC. If, at block 950, theUE determines that a PDSCH has not been successfully received for theCC, at block 970, the UE may determine whether the CC is a PCC or a SCC.If the CC is a PCC, at block 980 the UE may indicate “NACK” for the CC.If the CC is a SCC, at block 940 the UE may indicate “NACK/DTX” for theCC. The UE may then generate the state based on the indicated ACK, NACK,DTX or NACK/DTX for CCs (which may be scheduled, activated or configuredCCs) and map the generated state to a code-point in the codebook.

In another embodiment, full combining or grouping for NACK and DTX maybe used, where NACK and DTX are combined. For example, the states {ACK,ACK, NACK} and {ACK, ACK, DTX} may be combined into a single state (ACK,ACK, NACK/DTX). In this embodiment, if no PDCCH is detected for a CC, orif a PDCCH is detected for the CC but PDSCH is not received successfullyfor the CC, the UE may indicate “NACK/DTX” for the CC. Otherwise, the UEmay indicate “ACK” for the CC.

In an embodiment partial combining or grouping of states may be used. Insuch an embodiment, states may be combined, but such combining may beonly applied to a subset of CCs and not to all CCs. For example, only athird or half of the CCs respective NACK and DTX indications may becombined. The subset of CCs may be predetermined and/or configurable.CCs may be divided into two or more subsets, and in embodiment, CCs maybe categorized into the two or more subsets based on certain criteria,such as importance or priority (e.g., a “high importance” or “highpriority” CC set and a “low importance” or “low priority” CC set.)Partial combining or grouping may mitigate the performance impact due tostate combining.

Method 1000 of FIG. 10 is an exemplary non-limiting method ofimplementing such an embodiment. At block 1010, a UE may determinewhether a PDCCH is detected for a CC. If no PDCCH is detected, at block1020 the UE may determine if the CC belongs to a specified or indicatedsubset of CCs where the NACK and DTX indications associated with CCs inthe subset are to be combined. If the CC does not belong to a subsetwhere the NACK and DTX indications associated with CCs in the subset areto be combined, at block 1030 the UE may indicate “DTX” for the CC.However, if at block 1020 the UE determines that the CC belongs to aspecified or indicated subset of CCs where the NACK and DTX indicationsassociated with CCs in the subset are to be combined, at block 1040 theUE may indicate “NACK/DTX” for the CC.

If, at block 1010, the UE determines that a PDCCH is detected for a CC,at block 1050 the UE may determine whether a PDSCH has been successfullyreceived for the CC. If a PDSCH has been successfully received for theCC, at block 1060, the UE may indicate “ACK” for the CC. If a PDSCH hasnot been successfully received for the CC, at block 1070 the UE maydetermine if the CC belongs to a specified or indicated subset of CCswhere the NACK and DTX indications associated with CCs in the subset areto be combined. If the UE determines that the CC belongs to such asubset, at block 1040 the UE may indicate “NACK/DTX” for the CC. If, atblock 1070, the UE determines that the CC does not belong to a specifiedor indicated subset of CCs where the NACK and DTX indications associatedwith CCs in the subset are to be combined, at block 1080 the UE mayindicate “NACK” for the CC. The UE may generate the state based on theindicated ACK, NACK, DTX or NACK/DTX for CCs (which may be scheduled,activated or configured CCs) and map the generated state to a code-pointin the codebook.

In an embodiment, state reduction may be accomplished using PDCCH orPDSCH correlation. In some embodiments, while DCIs may be in the same ordifferent CCs, “missing PDCCH” may be correlated if the DCIs are in thesame CC. States may be correlated between PDCCHs in the same CC. If oneDTX is indicated, it may be likely that the other PDCCH is missed andthus DTX, too. A UE may combine {DTX, X} or {X, DTX} into a same state{DTX, DTX}, where X is a “don't care” (i.e., may be either ACK or NACK.)

There may also be a correlation between PDSCHs that may be used. Statesmay be correlated between PDSCHs in different CCs, for example, CCs thathave high correlation between them. If one ACK is generated for a CC, itis likely one ACK is also generated for the correlated PDSCH or CC. Ifone NACK is generated for a CC, it is likely that one NACK is alsogenerated for the correlated PDSCH or CC. One ACK and one NACK may stilloccur but with much lower probability. Therefore a UE may merge {ACK,NACK}, {NACK, ACK} and {NACK, NACK} into a single state (NACK, NACK) inthe codebook without causing significant degradation.

In one such embodiment, a UE may determine that there is at least oneNACK being generated for a CC, and may therefore indicate “All NACK”. Ifthe UE determines that ACKs are generated for all CCs, the UE mayindicate “All ACK”. Otherwise (e.g., where there is at least one ACK andone DTX but no NACK) the UE may indicate the state containing the ACKand DTX. Alternatively, the UE may indicate “All DTX”.

In an embodiment, if a PDCCH is detected for a CC, and a NACK isgenerated for the CC, the UE may indicate “NACK” for the CC and “NACK”also for the other CCs which are highly correlated with this CC (e.g.,in the same “high correlation” group). Otherwise, if ACKs are generatedfor all CCs, the UE may indicate “ACK” for all CCs. If a PDCCH is notdetected for a CC, the UE may indicate a DTX for the CC. The UE may alsoindicate “DTX” for the CCs whose PDCCHs are transmitted in the same CCas this CC.

In some embodiments, CCs may be ranked in order based on channelquality. It may be more likely to have NACK instead of DTX for CCshaving good channel quality. In an embodiment, if there is at least oneACK being generated for CCs, a UE may combine NACK and DTX for those CCsthat do not generate ACK and indicate “NACK/DTX” for those CCs. In thisembodiment, if there is no ACK being generated for CCs, the UE mayidentify the CC that has the worst channel quality whose PDSCH receptionresults in a NACK. This CC may be referred to as a reference CC. ThePDCCH reception for the CCs whose channel quality is worse thanreference CC is likely to result in DTX, while the PDSCH reception forthe CCs whose channel quality is better than reference CC is likely toresults in NACK. For CCs having worse channel quality than the referenceCC, the UE may indicate DTX for such CCs. For CCs having better channelquality than the reference CC, the UE may indicate NACK/DTX for suchCCs. A non-limiting exemplary ACK/NACK/DTX codebook (37 states, 6-bit)based on this embodiment is shown in Table 5.

TABLE 5 Transmission of ACK/NACK/DTX multiplexing for five componentcarriers ACK/NACK/DTX State Bits ACK, ACK, ACK, ACK, ACK 1 1 1 1 1 0ACK, ACK, ACK, ACK, NACK/DTX 1 1 1 1 0 0 ACK, ACK, ACK, NACK/DTX, ACK 11 1 0 1 0 ACK, ACK, ACK, NACK/DTX, NACK/DTX 1 1 1 0 0 0 ACK, ACK,NACK/DTX, ACK, ACK 1 1 0 1 1 0 ACK, ACK, NACK/DTX, ACK, NACK/DTX 1 1 0 10 0 ACK, ACK, NACK/DTX, NACK/DTX, ACK 1 1 0 0 1 0 ACK, ACK, NACK/DTX,NACK/DTX, NACK/DTX 1 1 0 0 0 0 ACK, NACK/DTX, ACK, ACK, ACK 1 0 1 1 1 0ACK, NACK/DTX, ACK, ACK, NACK/DTX 1 0 1 1 0 0 ACK, NACK/DTX, ACK,NACK/DTX, ACK 1 0 1 0 1 0 ACK, NACK/DTX, ACK, NACK/DTX, NACK/DTX 1 0 1 00 0 ACK, NACK/DTX, NACK/DTX, ACK, ACK 1 0 0 1 1 0 ACK, NACK/DTX,NACK/DTX, ACK, NACK/DTX 1 0 0 1 0 0 ACK, NACK/DTX, NACK/DTX, NACK/DTX,ACK 1 0 0 0 1 0 ACK, NACK/DTX, NACK/DTX, 1 0 0 0 0 0 NACK/DTX, NACK/DTXNACK/DTX, ACK, ACK, ACK, ACK 0 1 1 1 1 0 NACK/DTX, ACK, ACK, ACK,NACK/DTX 0 1 1 1 0 0 NACK/DTX, ACK, ACK, NACK/DTX, ACK 0 1 1 0 1 0NACK/DTX, ACK, ACK, NACK/DTX, NACK/DTX 0 1 1 0 0 0 NACK/DTX, ACK,NACK/DTX, ACK, ACK 0 1 0 1 1 0 NACK/DTX, ACK, NACK/DTX, ACK, NACK/DTX 01 0 1 0 0 NACK/DTX, ACK, NACK/DTX, NACK/DTX, ACK 0 1 0 0 1 0 NACK/DTX,ACK, NACK/DTX, NACK/DTX, 0 1 0 0 0 0 NACK/DTX NACK/DTX, NACK/DTX, ACK,ACK, ACK 0 0 1 1 1 0 NACK/DTX, NACK/DTX, ACK, ACK, NACK/DTX 0 0 1 1 0 0NACK/DTX, NACK/DTX, ACK, NACK/DTX, ACK 0 0 1 0 1 0 NACK/DTX, NACK/DTX,ACK, NACK/DTX, 0 0 1 0 0 0 NACK/DTX NACK/DTX, NACK/DTX, NACK/DTX, ACK,ACK 0 0 0 1 1 0 NACK/DTX, NACK/DTX, NACK/DTX, ACK, 0 0 0 1 0 0 NACK/DTXNACK/DTX, NACK/DTX, NACK/DTX, NACK/DTX, 0 0 0 0 1 0 ACK NACK/DTX,NACK/DTX, NACK/DTX, NACK/DTX, 0 0 0 0 0 1 NACK NACK/DTX, NACK/DTX,NACK/DTX, NACK, DTX 0 0 0 0 1 1 NACK/DTX, NACK/DTX, NACK, DTX, DTX 0 0 10 0 1 NACK/DTX, NACK, DTX, DTX, DTX 0 1 0 0 0 1 NACK, DTX, DTX, DTX, DTX1 0 0 0 0 1

In an embodiment, CCs may be partitioned into two or more partitions,each with fewer CCs than the total number of CCs. Because the number ofstates increases exponentially with the number of CCs, it may bedesirable to reduce the number of CCs. By CC partitioning, the number ofstates for each partition is significantly smaller due to the decreasednumber of CCs in each partition, and therefore fewer bits are requiredto represent the states in each partition.

For non-MIMO implementations, each CC has three states, namely ACK, NACKand DTX. This results in nine states (or 3²) for two CCs and 81 states(or 3⁴) for four CCs. The “All DTX” state may be {DTX, DTX} for two CCsand {DTX, DTX, DTX, DTX} for four CCs. The “All DTX” state may beexcluded from total states for joint coding because the “All DTX” statemay be implicitly indicated or detected by DTX detection at a receiverand may not need to be included for joint coding with other states. Ifthe “All DTX” state is excluded from total states for joint coding,there remain eight and 80 states for two CCs and four CCs respectively.For four CCs, it may require seven bits to represent all states. Thusseven bits are transmitted for each corresponding ACK/NACK/DTX stategenerated at a UE. For two CCs, it may require three bits to representthe all states. For two partitions where each has two CCs, only 3+3bits=6 bits in total may be needed to transmit all ACK/NACK/DTX statesfor both partitions generated at a UE.

Carrier partition may be used for joint coding and may transform anexponential increase in the number of states into a linear increase innumber of states. For M CCs, the total number of states exponentiallyincreases with the increase in M, with the number of states defined as3^(M)−1. For two CC partitions (one CC partition with y CCs, the otherCC partition with M−y CCs), the total number of states may semi-linearlyincrease with the increase in M, with the number of states defined as3^(y)−1+3^((M-y))−1, which requires log₂(3^(y)−1)+log₂(3^((M-y))−1) bitsto represent the states for both partitions. For example, for M=4 andy=2, the total number of states may be reduced to (3²−1)+(3²−1)=16states or 6(3+3) bits from 3⁴−1=80 states, or seven bits. The effectivecoding rate may be improved to 0.27 from 0.32 which results in about 0.8to 1 dB performance improvement for PUCCH joint coding. Table 6 showsthe number of states before and after partition, as well as the numberof bits required to represent the states used after partition, forseveral example embodiments.

TABLE 6 States before and after partition Num- Bits for ber of Totalstates before Total states after representing CCs partition partitionstates 5 3{circumflex over ( )}5 − 1 = 242 (8 bits) (3{circumflex over( )}2 − 1) + (3{circumflex over ( )}3 − 1) = 34 8 4 3{circumflex over( )}4 − 1 = 80 (7 bits) (3{circumflex over ( )}2 − 1) + (3{circumflexover ( )}2 − 1) = 16 6 3 3{circumflex over ( )}3 − 1 = 26 (5 bits)(3{circumflex over ( )}1 − 1) + (3{circumflex over ( )}2 − 1) = 10 4 23{circumflex over ( )}2 − 1 = 8 (3 bits) (3{circumflex over ( )}1 − 1) +(3{circumflex over ( )}1 − 1) = 4 2

In an embodiment, separate encoding of the DTX state of CCs configuredfor PDCCH reception may be used. In such embodiments, a UE may encodeand transmit certain information in the PUCCH in a given subframe. Suchinformation may include an indication of whether at least one DLassignment was detected from the PDCCH of each CC of a set of CCs, wherethe set of CCs may include at least one the set of CCs configured forPDCCH reception and the set of activated CCs configured for PDCCHreception. Such information may also include either status information(ACK/NACK) pertaining to the set of received transport blocks or statusinformation (ACK/NACK/DTX) pertaining to a set of transport blocks thatincludes transport blocks that may be received in CCs for which downlinkassignments can be signaled from the PDCCH of one of the CCs for whichit was indicated that at least one DL assignment was detected.

Status information transmitted may be encoded using any means or method,including those disclosed herein. For instance, a single bit may beutilized to indicate the state of a pair of transport blocks of a singleMIMO transmission, where the bit is set to ‘1’ (indicating ACK) whenboth transport blocks are successfully received, and ‘0’ (indicatingNACK) otherwise. In addition, where no DL assignment has been receivedon any DL CC, the UE may not transmit anything on the PUCCH.

The separate encoding embodiments described above may be especiallyuseful when a relatively small subset of configured (or activated) DLCCs are configured for PDCCH reception because the number of bitsrequired for indicating whether DL assignments were received in theseCCs is also small. Such embodiment may rely on the assumption that theremay be a significant correlation between error events where a DLassignment is missed when these DL assignments are transmitted from thesame DL CC. In this case, the probability that the UE misses a DLassignment but receives another DL assignment is very low when these DLassignments have been transmitted from the same DL CC, and thus there isvery little penalty in not reporting such events.

In an embodiment, variable length coding may be used, and state spacemay be encoded according to its probability. This may reduce the numberof bits to be transmitted. A guideline that “high probability” statesare encoded with fewer bits and “low probability” states are encodedwith more bits may be applied. Entropy encoding or Huffman encoding maybe used to encode the ACK/NACK/DTX states. Entropy encoding and Huffmanencoding are typically used for continuous bit sequences while in manyLTE systems PUCCH carries non-continuous bit sequences. Without suchconstraints the encoding for the states may have more flexibility. As aresult the code-point or the bits representing the states may havevariable length. By using entropy encoding or Huffman encoding, thenumber of bits to be transmitted in air may be fewer than average. Table7 illustrates these results with several non-limiting examples.

TABLE 7 Bits and probabilities for various states States BitsProbability Encoding {A A} 1 0.64 RM (20, 1) {A N} 0 0.12 RM (20, 1) {NA} 11 0.12 RM (20, 2) {A D} 10 0.04 RM (20, 2) {D A} 01 0.04 RM (20, 2){N N} 00 0.0225 RM (20, 2) {N D} 111 0.0075 RM (20, 3) {D N} 000 0.0075RM (20, 3)

In an example provided for illustrative purposes only, where two DLs arein use, and each DL uses only a single codeword, the probability of(CRC=good|PDCCH) or ACK is equal to 80%, NACK is 15% and DTX is 5%. Asseen in Table 7 there are 3²=9 states: {A A}=0.64, {A N}=0.12, {NA}=0.12, {A D}=0.04, {D A}=0.04, {N N}=0.0225, {N D}=0.0075, {DN}=0.0075, and {D D}=0.0025 (not transmit).

Method 1100 of FIG. 11 is an exemplary non-limiting method ofimplementing an embodiment. At block 1110, for a CC (that may be limitedto a scheduled, activated, or configured CC), a determination may bemade by a UE as to whether a PDCCH is detected for the CC. If no PDCCHis detected for the CC, the UE may indicate “DTX” for the CC at block1120. If a PDCCH is detected for the CC, at block 1130 the UE maydetermine if a PDSCH has been successfully received for the CC. If aPDSCH has not been successfully received for the CC, at block 1140 theUE may indicate “NACK” for the CC. If a PDSCH has been successfullyreceived for the CC, at block 1150 the UE may indicate “ACK” for the CC.

At block 1160, the UE may generate a state based on the indicated ACK,NACK or DTX for each CC. In some embodiments, the UE may be configuredto generate a state for all CCs. At block 1165, the UE may determine anoccurrence probability for the state. If the state generated at block1160 is marked with or otherwise associated with a high occurrenceprobability or equivalent category, at block 1170 the UE may map thegenerated state to a short length code point in the codebook. If thestate generated at block 1160 is associated with a medium occurrenceprobability, at block 1180 the UE may map the generated state to amedium length code point in the codebook. If the state generated atblock 1160 is associated with a low occurrence probability, at block1190 the UE may map the generated state to a long length code point inthe codebook.

In other embodiments, unequal error protection may be used. A statespace may be partitioned into two or more partitions and unequal codingmay be applied to each partition. The criteria for determining thepartition may be based on the different performance requirement forstates. For example, a NACK error may be more critical than an ACKerror. Probability of NACK to ACK may be more important than theprobability of ACK to NACK. The states containing NACKs may be encodedwith a higher coding strength or have fewer information bits. States maybe distinguished by the number of NACKs relative to other states, andstates may be partitioned into several categories based on thatdistinction. For example, one category of states may be “NACKs are morenumerous than ACKs”, and another category of states may be “ACKs aremore numerous than or the same number as NACKs.” Stronger coding may beapplied to the first category of states with more NACKs than ACKs andweaker coding may be applied to the second category of states with moreACKs than NACKs or the same number of ACKs and NACKs.

For example, in an embodiment with M=4 CCs, there may be 80 states intotal. 80 states may be partitioned into two partitions, one containing16 states and the other containing 64 states. This embodiment requiresfour bits and six bits respectively to support unequal coding ascompared to a codebook using seven bits without unequal codingcapability. RM coding may be used in such an embodiment, with (20, 4)and (20, 6) being used for partitions respectively.

Method 1200 of FIG. 12 is an exemplary non-limiting method ofimplementing such an embodiment. At block 1210, a UE may determine if aPDCCH is detected for a CC. Note that in some embodiments, thedetermination may be limited to a scheduled, activated, or configuredCC. If no PDCCH is detected for the CC, at block 1220 the UE mayindicate “DTX” for the CC. If a PDCCH is detected for the CC, at block1230, the UE may determine whether a PDSCH has been successfullyreceived for the CC. If a PDSCH has not been successfully received forthe CC, at block 1240 the UE may indicate “NACK” for the CC. If a PDSCHhas been successfully received for the CC, at block 1250 the UE mayindicate “ACK” for the CC.

At block 1260, the UE may generate a state based on the indicated ACK,NACK or DTX for the CC. In some embodiments, the UE may be configured togenerate a state for all CCs. At block 1265, the UE may determine if thestate generated at block 1260 is associated with a “high errorprotection” partition or a “normal error protection” partition. If thegenerated state is associated with a “high error protection” partition,at block 1270, the UE may map the generated state to a code point towhich a “strong” channel coding is applied in the codebook. If thegenerated state is associated with a “normal error protection”partition, at block 1280, the UE may map the generated state to a codepoint to which a “regular” channel coding is applied in the codebook.

Method 1300 of FIG. 13 is an exemplary non-limiting method ofimplementing an embodiment. At block 1310, a UE may determine if a PDCCHis detected for a CC. Note that in some embodiments, the determinationmay be limited to a scheduled, activated, or configured CC. If no PDCCHis detected for the CC, at block 1320 the UE may indicate “DTX” for theCC. If a PDCCH is detected for the CC, at block 1330, the UE maydetermine whether a PDSCH has been successfully received for the CC. Ifa PDSCH has not been successfully received for the CC, at block 1340 theUE may indicate “NACK” for the CC. If a PDSCH has been successfullyreceived for the CC, at block 1350 the UE may indicate “ACK” for the CC.

At block 1360, the UE may generate a state based on the indicated ACK,NACK or DTX for the CC. In some embodiments, the UE may be configured togenerate a state for all CCs. At block 1365, the UE may determinewhether the generated state has more NACKs than ACKs. If the generatedstate has more NACKs than ACKs, at block 1370 the UE may map thegenerated state to a “short” code point in the codebook. If thegenerated state has the same number of NACKs and ACKs, or more ACKs thanNACKs, at block 1380 the UE may map the generated state to a “long” codepoint in the codebook. Note that the disclosed unequal coding methodsmay be used in combination with any other embodiments disclosed herein,include state subspace methods.

In an embodiment, the number of ACK/NACK bits that need to be fed backdepends on DL-UL configuration. In an embodiment, for example in anLTE-A TDD system, the number of ACK/NACK fed back bits may be dependenton DL-UL configuration as well as the number of aggregated componentcarriers. For example, for a 4DL:1UL subframe configuration and fivecarrier aggregation, a UE may feed back 40 ACK/NACK bits (e.g., whereimplicit DTX and DL MIMO is used for all five carriers.) There may be atleast two ACK/NACK feedback modes in an embodiment. One such mode may beACK/NACK multiplexing, and another such mode may be ACK/NACK bundling.Either or both of these feedback modes may utilize feedback reductionusing spatial-domain and/or time-domain (subframe) bundling. The numberof feedback ACK/NACK bits may be 10 bits in LTE-A embodiments using FDD.Therefore, to reduce feedback overhead in TDD systems so that overheadis comparable to LTE-A FDD, the full feedback of ACK/NACK bits may bereduced at the cost of performance degradation in a TDD system. Afeedback mode that may be used with ACK/NACK bundling may be ACK/NACKmultiplexing with partial bundling. Another feedback mode may be fullACK/NACK bundling.

In an embodiment, a UL indicator may be used. A total number of thedetected DL assignments may be fed back for both ACK/NACK multiplexingwith partial bundling and full bundling. The number of detected DLassignments may use a modulo 4 operation to reduce the overhead. Theremay be no need to signal a DL indicator to downlink assignment indicator(DAI) for ACK/NACK multiplexing with partial bundling or full bundling.The last PDCCH miss problem that may be found in some legacy systems maybe eliminated or solved. In an embodiment using UL feedback with partialbundling, time-domain (i.e., subframes) partial bundling may be usedfirst and then CC multiplexing may be performed. Alternatively, or inaddition, frequency-domain (i.e., CC) partial bundling maybe used firstthen downlink subframe multiplexing may be performed.

In an embodiment, time-domain (subframes) partial bundling with CCmultiplexing may be used. In such an embodiment, a UE may monitor (e.g.,count) how many ACKs (i.e., the corresponding PDSCH CRC is detectedsuccessfully) are detected for each CC. For example, FIG. 14 shows anexemplary non-limiting configuration 1400 with a 4DL:1UL (M=4) subframeconfiguration and a five (N=5) component carriers aggregation. In thisembodiment, DAI may not be signaled in the DL. For each CC, the UE maycount the number of ACKs for all DL subframes (four downlink subframesare used in the example shown in FIG. 14.) The UE may report {2, 1, 2,2, 2} ACKs for CC1, CC2, CC3, CC4 and CC5 respectively.

The total number ACKs or NACKs for all CCs may be multiplexed andjointly encoded. This may allow for the use of 10 ACK/NACK feedback bits(two bits for each CC, with N=5 CCs.) The total number of ACKs for eachCC may be fed back using a modulo 4 operation. The two feedback bitsb(0), b(1) for each CC and their corresponding mapping to multipleACK/NACK responses according to an exemplary non-limiting embodiment areshown in Table 8. The two ACK/NACK feedback bits per CC may be jointlyencoded and multiplexed. If there is no ACK detected in a configured CC,a UE may report NACK.

TABLE 8 Mapping between multiple ACK/NACK responses and b(0), b(1) forCC i Number of ACKs b(0), b(1) 0 or None (UE detects at least one DLassignment is missed) 0, 0 1 1, 1 2 1, 0 3 0, 1 4 1, 1 5 1, 0 6 0, 1 71, 1 8 1, 0 9 0, 1

In an embodiment, frequency-domain (CC) partial bundling with subframemultiplexing may be used. Similar to the time-domain (subframes) partialbundling with CC multiplexing embodiment disclosed above, a UE may countthe total number of ACKs for all configured CCs for each DL subframe. Asshown in FIG. 14, a UE may report {4, 1, 2, 2} ACKs for downlinksubframe 1, subframe 2, subframe 3, and subframe 4, respectively. Thetotal number ACKs for each DL subframe may be multiplexed and jointlyencoded. The total number of ACK/NACK feedbacks may be equal to twotimes the number of DL subframes in a TDD configuration. In thisexample, eight feedback bits (two bits for each DL subframe and M=4downlink subframes) may be sufficient for ACK/NACK feedback. An exampleof the two feedback bits b(0), b(1) for each subframe and theircorresponding mapping to multiple ACK/NACK responses are shown in Table9.

TABLE 9 Mapping between multiple ACK/NACK responses and b(0), b(1) forsubframe i Number of ACKs b(0), b(1) 0 or None (UE detect at least oneDL assignment is missed) 0, 0 1 1, 1 2 1, 0 3 0, 1 4 1, 1 5 1, 0

In an embodiment, full ACK/NACK bundling may be used. In such anembodiment, there may be no need to distinguish time-domain bundling orfrequency-domain bundling for full bundling because this implementationof such an embodiment may only report a single number representing thetotal number of ACKs for all DL subframes and CCs. Also, a modulo 4operation may be used on the reported ACKs. Therefore, only two bits maybe used for ACK/NACK feedback. The two feedback bits b(0), b(1) andtheir corresponding mapping to multiple ACK/NACK responses are shown inTable 10. For a UE operating in a power-limited configuration, theoverhead of ACK/NACK feedback may be optimized and service coverage maybe increased or maintained.

TABLE 10 Mapping between multiple ACK/NACK responses and b(0), b(1)Number of ACKs b(0), b(1) 0 or None (UE detect at least one DLassignment is missed) 0, 0 1, 4, 7, 10, 13, 16, 19 1, 1 2, 5, 8, 11, 14,17, 20 1, 0 3, 6, 9, 12, 15, 18 0, 1

In an embodiment, a DL indicator or DAI may be used. A two-bitDAI(modulo x or modulo 4) may be used as an indicator of the total numberof scheduled PDCCHs/CCs for each DL subframe. There may be no need toreport a total number of ACKs in UL (i.e., no need for a UL indicator.)This embodiment may be used for ACK/NACK multiplexing withfrequency-domain (CC-domain) partial bundling or full ACK/NACK bundling,for example as disclosed herein. For embodiments using spatial bundling(e.g., where DL is in MIMO mode), the maximum number of UL ACK/NACKfeedback bits may be nine. Unlike time-domain partial bundling used insome legacy systems, the last PDCCH miss-detection problem may besolved. Also, the size of DAI may be compatible with legacy systems.Non-limiting example values of downlink indicators or DAIS are shown inTable 11.

TABLE 11 Values of DL indicators or DAIs DL Indicator or DAIMSB, LSBNumber of CCs with PDSCH transmission 0, 0 1 or 5 0, 1 2 1, 0 3 1, 1 0or 4

In an embodiment, two-bitDAIs may be signaled in DL and a UE may bundleACK/NACKc in the CC-domain to generate one to two bits per DL subframe(CC-domain partial bundling for each downlink subframe.) The bits ofeach DL subframe after bundling may be multiplexed and jointly encodedas UL ACK/NACK feedback bits. Since DAI may be an indicator of the totalnumber of scheduled DL assignments for each DL subframe, the UE maydetect whether there is PDCCH missed detection or not for each DLsubframe. Therefore, the UE may generate bundled bits in the CC-domain.In the non-limiting example configuration 1500 illustrated in FIG. 15,there are two DL assignments that are miss-detected in DL subframe 2 andsubframe 4 for CC2 and CC4 respectively. The value of ACK/NACK feedbackis 0 (e.g., for SIMO) or 00 (e.g., for MIMO) for subframes 2 and 4, andthe value of ACK/NACK feedback is 1 (e.g., for SIMO) or 11 (e.g., forMIMO) in subframes 1 and 3. Those feedback bits of each DL subframe maybe multiplexed and jointly coded. Hence, there may be no need to reportthe total number of ACKs as a UL indicator. If spatial bundling is usedfor a 9DL:1UL (M=9) configuration in MIMO mode, carrier-domain bundlingmay be associated with spatial bundling in order to save more ULACK/NACK feedback overhead. In this case the maximum number of ULACK/NACK feedback bits may be nine. Even in embodiments using a TDDDL-UL configuration (9DL:1UL), the number of UL ACK/NACK bits may stillbe less than the 10 bits supported in LTE-A FDD. Unlike in some legacyTDD time-domain bundling configurations, the last PDCCH miss detectionmay be solved because a UE may have the information regarding how manyDL assignments are scheduled in a particular DL subframe.

In an embodiment, a combination of a DL indicator or a DAI and an a ULindicator may be used. A DL indicator or DAI may be applied in DLsignaling. A DL indicator or DAI may indicate a total number ofscheduled DL assignments by a base stations (e.g., an eNodeB) for allCCs for each subframe. This may be implemented in a similar manner asthe solution described herein in regard to Table 11. Another examplevalue of DL indicators or DAIS is shown in Table 12. A UL indicator mayindicate the total number of ACKs. A UL indicator in this embodiment maybe similar to the UL indicator described above. A UE may save transmitpower when in a mode of full ACK/NACK bundling when full ACK/NACKbundling is being used.

TABLE 12 Values of DL indicators or DAIs DL Indicator or Number ofsubframes with PDSCH DAI MSB, LSB transmission 0, 0 1 or 5 or 9 0, 1 2or 6 1, 0 3 or 7 1, 1 0 or 4 or 8

If a two-bit DL indicator or DAI (modulo 4) is signaled in the DL when afull bundling mode is in use, a UE may be configured to detect wherePDCCHs are miss-detected in each DL subframe. Upon detecting a missedPDCCH, a UE may signal DTX (i.e., there is no physical transmission.) Inthis way, the UE may save transmit power when in full bundling mode.This may be crucial if the UE is power-limited. In the non-limitingexample configuration 1600 illustrated in FIG. 16, a UE may havedetected at least two missing DL assignments at DL subframe 2 and 4. TheUE may not transmit any ACK/NACK feedback since the base station (e.g.,an eNodeB) may detect a DTX and may retransmit all data when the UE isin full ACK/NACK bundling mode. Furthermore, this embodiment does notincrease the size of the DAI field, and may be backward compatiblelegacy systems (e.g., LTE R8) in terms of DCI format size.

In an embodiment, two-bit DAI may be reclaimed as carrier indicationfield (CIF) bits to reduce signaling overhead. If there is no need tosignal DL DAI in DL (or if DAI may not be used), two-bit DAIS in a DCIformat may be reclaimed as CIF bits, and therefore PDCCH overhead may bereduced.

In an embodiment, an extended DL indicator or extended DAI may be used.Two parts of DAI may be used, i.e., DL DAI=(DAI1, DAI2)=(3 bits, 2 bits)or (2 bits, 2 bits) where DAI1 may be the number of scheduled PDCCH/CCsfor each DL subframe and DAI2 is the CC-first counter acrossCC/subframe. There may be no need to report the total number of ACKs inUL (i.e., no need for a UL indicator.) This embodiment may be used forACK/NACK multiplexing with frequency-domain (CC-domain) partial bundlingor full ACK/NACK bundling. For implementations using spatial bundling(e.g., DL is in MIMO mode), the maximum number of UL ACK/NACK feedbackbits may be nine. Unlike time-domain partial bundling in some legacysystems, the last PDCCH miss-detection problem may be solved.

In an embodiment, there may be two parts in DL DAI design, i.e., DAI=(DAI1, DAI2). The first part of DAI (i.e., DAI1) may be equal to theDAI as disclosed above, i.e, an indicator of the total scheduledPDCCHs/CCs for each DL subframe. Since DAI1 may be an indicator of thetotal scheduled PDCCHs/CCs for each DL subframe, it may share the sameproperties, such as there may be no need to report a total number ofACKs in UL, enabling ACK/NACK multiplexing with CC-domain partialbundling or full ACK/NACK bundling, the maximum of UL ACK/NACK feedbackbits may be equal to nine associated with spatial bundling, and the lastPDCCH miss-detection problem may be solved. DAI2 may a sequentialcounter that counts CC-domain first as the second part of DAI design.This embodiment may detect a case when there is only one CC beingscheduled in a DL subframe. In the non-limiting example configuration1700 illustrated in FIG. 17, at DL subframe 2 there may be only onePDCCH scheduled and the UE may have miss-detected that PDCCH. This mayresult in the UE not being aware whether PDCCH is being scheduled at DLsubframe 2 or not. DAI2 can compensate for this issue by the realizationof CC-domain counter. In the example shown in FIG. 17, the UE maydetermine that there is a missed PDCCH detection. Therefore, the UE maygenerate the right full bundling state (i.e., NACK) instead of ACK.

In an embodiment, three parts of DAI may be used, i.e., DL DAI=(DAI1,DAI2, DAI3)=(3 bits, 2 bits, 2 bits) or (2 bits, 2 bits, 2 bits), whereDAI1 may be the number of scheduled DL assignments, DAI2 may be theCC-first counter across CC/subframe, and DAI3 may be a two bits counter(e.g., as used in some legacy systems.)

Note that optimal DL DAI design may be used at the cost of increasedoverhead. Hence, a UE may perform ACK/NACK multiplexing with eitherCC-domain or time-domain bundling. Also, the last PDCCH miss-detectionissue may be solved since DAI1 may present the number of scheduled DLassignments.

As set forth in the descriptions of several embodiments above, detectinga PDCCH for a CC may be desired. It may also be desirable to determine aPDCCH reception status more granularly. More specifically, it may beuseful to detect a missed PDCCH and false positive detection of a PDCCH.In an embodiment, DL control signals or DCIs transmitted by the network(e.g., from an eNodeB) to a UE may contain an indicator representativeof the number in sequence or count of control messages sent over apredetermined reference time period. For example, a reference timeperiod may be one subframe. The indicator may be an increasing countermodulo of a predetermined value. Alternatively, the set of DL controlsignals or DCI's that provide such an in-sequence or count indicator tothe UE as sent by a base station (e.g., an eNodeB) may specificallyinclude all DL assignment DCI's sent during the reference time periodover all configured or activated CCs for that UE.

In another embodiment, a DL control signal, or DCI's transmitted by thenetwork (e.g., from an eNodeB) to a UE, may contain an indicatorrepresentative of the total number of control messages sent over apre-determined time reference time period. In one such embodiment, thisindicator may be an absolute value in a predetermined range. Forexample, this set of DL control messages carrying an indicationrepresentative of a total number of DL assignment messages sent to theUE in that subframe may be any or all occurrence(s) of a UL grant DCIover a subframe period representative for the set of DL assignment DCIssent during the reference time period over all configured or activatedCCs for the UE. These embodiments, the sequence indicator embodiment,and the total number of control message embodiment may be combined orused independently.

Note that, as used herein, Downlink Control Information, or “DCI”, mayrefer to a DL signalling message for transmission control purposes sentby the network and received by a UE. In the disclosed embodiments,unless otherwise specified, the term “DCI” however used, withoutlimiting any such embodiments, may refer to a DL signaling message forwhich a UE is expected to transmit uplink control information (e.g.,HARQ ACK/NACK.) While the present embodiments include methods totransmit uplink feedback for downlink transmission(s) and thus mainlyrefer to a DCI that would typically schedule one or more PDSCHtransmission(s), the applicability of the embodiments described hereinis not limited to this specific case. For example, a DCI received by aUE which DCI signals (de)activation of a configured assignment such as“SPS release”, of a configured grant or of a configured SCell, may alsorequire HARQ ACK/NACK transmission from the UE.

Therefore, although not describing such particular embodiments, oneskilled in the art will appreciate that the embodiments disclosed may beequally applicable to any type of DCIs and the corresponding UL controlsignalling or subset thereof, as well as in case of UL control messagesand DL HARQ feedback on a Physical Hybrid Automatic Repeat RequestIndicator Channel (PHICH). For example, disclosed embodiments may beequally applicable to the case where a DCI is used to grant PUSCHresources to a UE, and the associated DL HARQ feedback on PHICH.

Without limiting any disclosed embodiment, to refer to any DLtransmission for which the UE is expected to transmit HARQ ACK/NACKfeedback, the term “DCI and/or PDSCH” may be used hereafter and shall beunderstood to at least include any successfully decoded DCI on a PDCCHthat indicates either a PDSCH assignment and/or control information suchas (de)activation of a previously configured DL assignment and/or ULgrant, and any PDSCH transmission for which the UE attempted decodingusing a HARQ process.

When referred to herein, the term “PUCCH resource” may generally includeeither the PUCCH indices (or index), the PUCCH transmission format (ortransmission method e.g., format 1/1a/1b, format 2/2a/2b, DFT-S-OFDM orformat 3), the PUCCH ACK/NACK location (e.g., RB, orthogonal sequenceindex, cyclic shift), the number of HARQ ACK/NACK bits carried in theformat (including bits implicitly derived e.g., using channelselection), also possibly the use of a scrambling code for thetransmission or any of those in combination.

When referred to herein, the term “dynamic PUCCH allocation method” mayrefer to a method by which a UE may determine PUCCH resource to usebased on the control signaling received in the subframe for which HARQACK/NACK may be transmitted. An example of such method is the use of arule based on the first CCE of the decoded DCI (a reference DCI) similarto the LTE R8 or LTE R9 PUCCH resource allocation.

When referred to hereafter, the term “semi-static PUCCH allocationmethod” may refer to a method by which a UE may determine the PUCCHresource to use based on, e.g., a semi-static configuration of the UE.An example of such a method is the LTE R8 or LTE R9 HARQ ACK/NACK PUCCHallocation for DL SPS transmissions.

A UE configured or activated to receive on more than one serving cell orCC may receive at least one DL control signal, or DCI, containing atleast one indicator representative of the number in sequence or count,or total number of control messages. The UE may determine, based on theindicator field, if the set of decoded DCIs is complete, or if one ormore are missing. The UE may take a first action, such as generating andtransmitting a HARQ ACK/NACK signal, if the set of decoded DCIs isdetermined to be complete. The UE may take a second distinct action,such as transmitting no HARQ ACK/NACK signal, if it determines that theset of decoded DCIs is not complete. For example, the UE may determinethat it has missed at least one PDCCH (or got a false positive) based ona comparison between the number of successfully decoded DCI(s) in agiven sub-frame and a signaled value of the total number of items forwhich the UE is expected to send HARQ ACK/NACK feedback for saidsub-frame.

In an embodiment, considering only PDSCH assignments, a UE maysuccessfully decode at least one DCI for a PDSCH transmission in a givensub-frame, determine, from a field of said DCI, a number of PDSCHassignments for said sub-frame. The UE may also determine, based acomparison of the number of successful DCIs with the indicated number ofPDSCH assignment for said sub-frame, whether it has missed a DCI (e.g.,whether the number of successful DCIs is less than the indicated number)or has had a false positive (e.g., whether the number of successful DCIsis higher than the indicated number.) If the number of successful DCIsis the same as the indicated number, the UE may determine that it hasdecoded all its DCIs for the subframe.

In an embodiment, any DCI for which the UE is expected to transmit HARQACK/NACK feedback may be considered. For example, the number ofsuccessful DCIs may include control signaling for which the UE isexpected to transmit HARQ ACK/NACK feedback.

Upon determining which UCI and/or feedback data to transmit to a basestation (e.g., an eNodeB) using PUCCH, a UE may determine the particularPUCCH resources to be used to transmit such UCI and/or feedback data. Inan embodiment, a UE may determine a PUCCH resource from a set ofpossible PUCCH resources as well as the number of HARQ ACK/NACKinformation bits to transmit. The selected resource may be used, forexample, to transmit HARQ ACK/NACK feedback for at least one DLtransmission (e.g., DCI and/or PDSCH) in a given sub-frame based on atleast one, and in an embodiment a combination of any, of severalcriteria.

Included among such criteria are the number of serving cells configured(e.g., by RRC) and the number of serving cells active in the subframe.Also included among such criteria are the number of codewords that maybe received in the PDSCH of a given serving cell in a single sub-frame,depending on the configured downlink transmission mode (e.g., spatialmultiplexing, MIMO) of each serving cell. In such an embodiment, onlysecondary serving cell(s), or Scells, activated by Fast (De)ActivationCommand (FAC) signaling may be included, in particular FAC signalingwhich may itself be subject to HARQ ACK/NACK feedback from the UE to thebase station. In an embodiment, secondary cell(s) that may bedeactivated implicitly may be included, i.e., for secondary cell(s) thatwere not deactivated by FAC signaling. Also among such criteria are thenumber of DL assignments received in said subframe, in an embodiment,including any configured DL assignments, i.e., for Semi-PersistentScheduling (SPS) and/or signaled in one or more DCI(s). Also among suchcriteria is the location (i.e., the number or index) of the ControlChannel Element(s) (CCE(s)) (or, in an embodiment, only the first CCE)of the decoded DCI corresponding to a DL assignment in said subframe,e.g., at least one of whether or not the CCE(s) is in a specific searchspace, such as the one corresponding to the PCell and whether or not theCCE(s) is in a specific portion of said search space.

Further criteria that may be used in an embodiment include acharacteristic of the PDSCH corresponding to a DL assignment in saidsubframe, e.g., whether the PDSCH corresponds to a PCell or to an SCellof the UE's configuration and a characteristic of the successfullydecoded DCI (DCI Characteristics, as described further herein)corresponding to the DL assignment(s) in said subframe, in anembodiment, when the CIF corresponds to a PCell of the UE'sconfiguration. Further criteria include a configuration (e.g., RRC)indicating which resource to use, in an embodiment, signaled in one ormore DCI(s), and in an embodiment, a set of PUCCH resources (e.g.,indices) to be used for channel selection.

Also included among such criteria are the number of dedicated PUCCHresources, if any, configured for the UE (e.g., by RRC), on anembodiment, the number of PUCCH format 1b indices. Further criteriainclude the number of DCI messages received in said subframe and forwhich the UE shall report HARQ ACK/NACK, and the number of HARQ ACK/NACKbits for each DCI message, in an embodiment, based on some explicitvalue received in at least one of the decoded DCI(s), and, in anembodiment, based on an index to a specific PUCCH resource or set ofresources received in at least one of the decoded DCIs. Additionalcriteria that may be used in an embodiment are whether or not the UE isconfigured to use bundling for transmission of HARQ ACK/NACK on PUCCHand whether or not the UE has detected incorrect PDCCH reception for thesubframe.

The UE may determine the number of HARQ ACK/NACK information bits totransmit according to at least one of the above methods, and select thePUCCH ACK/NACK resource accordingly. The PUCCH resource(s) (i.e., formatand index) selected, as well as whether channel selection is used, maybe a function of at least one of the number of configured serving cells,the number of ACK/NACK information bits to transmit (i.e., basedonhigher layer configuration, the number of successfully decoded DCIsand/or PDSCH, and/or the number of codewords for each PDSCH), whether ornot ACK/NACK bundling is used, and if the UE has detected incorrectPDCCH reception.

In an embodiment, a semi-static selection method may be used, where theselection is a function of a UE's configuration and in particular of thenumber of configured serving cell(s). In such an embodiment, when the UEis configured for single carrier operation (i.e., the UE is configuredto operate with a single serving cell, i.e., a single UL CC and a singleDL CC), the UE may select a PUCCH resource using any method, includinglegacy methods. For instance, where a legacy method is used, the UE mayuses the resource index n_(PUCCH)=n_(CCE)+N⁽¹⁾ _(PUCCH), where n_(CCE)may be the number of the first CCE used for transmission of thecorresponding DCI (containing a DL assignment or a SPS release) and N⁽¹⁾_(PUCCH) may configured by higher layers. A corresponding DCI may benormally received in a previous subframe according to pre-determinedrules, such as subframe n−4 in case of FDD mode, where n is the subframewhen the PUCCH is transmitted. But when the UE is configured formulticarrier operation (i.e., the UE is configured with at least oneUL/DL PCC pair (i.e., a PCell) and a number N of DL SCC(s), where N≥1(i.e., at least one SCell)), the UE may use the same PUCCH ACK/NACKresource supporting transmission of the corresponding HARQ ACK/NACKinformation (including consideration of the number of possible codewordsfor each DL CCs). In this embodiment, the same PUCCH ACK/NACK resourcemay be used until the UE is it reconfigured by the base station (e.g.,an eNodeB.)

In a variation of the disclosed semi-static selection method, a UEconfigured for multicarrier operation may perform PUCCH resourceselection as described, with the exception of when HARQ ACK/NACK istransmitted for DL transmissions (i.e., DCI and/or PDSCH) on the PCell.In that case, in this embodiment the UE may select a PUCCH resourceusing a legacy resource selection method or any other method that may beused for the single carrier operation.

In an embodiment, a dynamic selection method may be used where theselection is a function of a UE's configuration and of the number nbitsof HARQ ACK/NACK information bits to transmit in each subframe. Method1800 of FIG. 18 is an exemplary non-limiting method of implementing suchan embodiment. At block 1810, the UE may determine whether it isconfigured for single carrier or multicarrier operation. Note that thisdetermination may be merely operating the UE as configured, i.e., in theconfigured single carrier or multicarrier mode. If the UE is configuredfor single carrier operation (i.e., the UE is configured to operate witha single UL CC and a single DL CC), at block 1820 the may UE select aPUCCH resource using a legacy method or any other method that may beused in a single carrier environment. For example, if DL MIMO is notconfigured (i.e., nbits=1), the UE may use PUCCH format 1a, and if DLMIMO is configured (i.e., nbits=2), the UE may use PUCCH format 1b.

In an embodiment, when at block 1810 the UE determines that it isconfigured for multicarrier operation, if at block 1830 the UEdetermines that it is configured to use two DL CCs and where the UE isconfigured with exactly one UL/DL PCC pair (i.e., one PCell) and exactlyone DL SCC (SCell), at block 1840 the UE may select a PUCCH resourceaccording to a legacy method or any other method that may be used in asingle carrier environment with PUCCH format 1b.

Alternatively, if at block 1810 the UE determines that it is configuredfor multicarrier operation (i.e., the UE is configured with (at least)one UL/DL PCC pair (i.e., a primary serving cell or PCell) and a numberN of DL SCC(s), where N≥1 (i.e., at least one secondary serving cell orSCell)), or if at block 1830 the UE determines that it is receiving aDCI for DL assignment (i.e., from a PDSCH transmission) or SPS releaseonly on a single serving cell, at block 1850 the UE may determine avalue of nbits and determine whether nbits fits into one of severalcategories. If at block 1850 the UE determines that nbits<m (where m maybe some threshold value or number of HARQ ACK/NACK information, forexample configured on a UE or provided by a base station) at block 1860the UE may use a dynamic PUCCH allocation method similar to the legacymethod where PUCCH format 1a is used when nbits=1 and PUCCH format 1b isused otherwise. With this legacy method the UE may use the resourceindex n_(PUCCH)=n_(CCE)+N⁽¹⁾ _(PUCCH) where n_(CCE) is the number of thefirst CCE used for transmission of the corresponding DCI assignment andN⁽¹⁾ _(PUCCH) is configured by higher layers. In an embodiment, thistype of PUCCH allocation method may be used only for a PDSCHtransmission on the primary cell, or PCell of the UE's configuration,but not for a PDSCH transmission on a secondary cell, or Scell.

If at block 1850 the UE determines that m≤nbits<n, (where n may beanother threshold value or number of HARQ ACK/NACK information, forexample configured on a UE or provided by a base station) at block 1870the UE may use a transmission method based on channel selection usingmultiple (ncspucch) PUCCH format 1b resources in order to allocate PUCCHresources. If at block 1850 the UE determines that nbits≥n, at block1880 the UE may use a DFT-S-OFDM-based method of PUCCH resourceallocation. In some embodiment, a DFT-S-OFDM-based method may be used bya UE when m=3, n=4, and ncspucch=2, or when m=3, n=5, and ncspucch=4.

In an embodiment, a dynamic selection method may be used where theselection may be a function of the activation state of the CCs of theUE's configuration and of the number nbits of HARQ ACK/NACK informationbits to transmit in each subframe. In such an embodiment, the UE mayselect, in a given subframe, a PUCCH resource using a legacy method, orany other method that may be used in a single carrier environment, ifthe UE is configured for single carrier operation or if the UE isconfigured for multicarrier operation and all DL SCCs are in adeactivated state (e.g., if the UE is configured with at least one UL/DLPCC pair (i.e., a PCell) and a number N of DL SCC(s), where N≥1 (i.e.,at least one SCell), but all N DL SCCs are in a deactivated state.) Inthis embodiment, the UE may otherwise use a PUCCH ACK/NACK resourcesupporting transmission of the HARQ ACK/NACK information (includingconsideration of the number of possible codewords for each DL CCs)corresponding to the number of CCs that were active in the subframe forwhich ACK/NACK feedback is transmitted on PUCCH.

In yet another embodiment, a UE may be configured to use dynamicexplicit selection method where the selection is a function of receivedcontrol signaling. In such an embodiment, when the UE is configured forsingle carrier operation, the UE may select a PUCCH resource using alegacy method or any other method that may be used in a single carrierenvironment. For instance, where a legacy method is used, the UE may usethe resource index n_(PUCCH)=n_(CCE)+N⁽¹⁾ _(PUCCH), where n_(CCE) may bethe number of the first CCE used for transmission of the correspondingDCI assignment and N⁽¹⁾ _(PUCCH) may be configured by higher layers.When the UE is configured for multicarrier operation, (i.e., the UE isconfigured with (at least) one UL/DL PCC pair (i.e., a primary servingcell or PCell) and a number N of DL SCC(s), where N≥1 (i.e., at leastone SCell)), the UE may use the PUCCH resource indicated in the controlsignaling (e.g., PDCCH DCI or FAC signaling (e.g., using MAC CE)) withan index (i.e., ACK/NACK Resource indicator (ARI)) to a resourceconfigured by RRC.

A UE may determine the number of HARQ ACK/NACK information bits totransmit according to at least one of the above embodiments, and maythen determine a location for PUCCH ACK/NACK, which may also be referredto as a PUCCH index or a PUCCH ACK/NACK index. In an embodiment, a UEconfigured to receive at least one downlink control message (e.g., DCI)in a given time interval (e.g., a subframe) may determine an uplinkresource (e.g., a PUCCH index) for transmission of an uplink signalcarrying feedback information (e.g., HARQ ACK/NACK feedback) using asignaled or a statically configured reference DCI.

Alternatively, a UE may dynamically determine the location of a PUCCHACK/NACK resource by dynamically determining at least one reference DCI.The reference DCI may be a successfully decoded DCI in a given subframe.The UE may determine the PUCCH ACK/NACK index from, for example, thefirst CCE of the reference DCI. The reference DCI may be dynamicallydetermined based on explicit signaling in a DCI format, e.g., a 1-bitflag indicating whether or not a DCI is a reference DCI, and/orsignaling received from the network and/or based on a configuration ofthe UE. For example, the reference DCI may correspond to at least one ofa DCI received in a specific serving cell (e.g., for the PCell of theUE's configuration), a DCI received for a transmission on the PDSCH of aspecific serving cell (e.g., for the PDSCH of a PCell of the UE'sconfiguration), and a DCI received for control signaling for a specificserving cell (e.g., for SPS activation on a PCell of the UE'sconfiguration.)

In an embodiment, the reference DCI may be dynamically determined basedon one or more characteristic of the successfully decoded DCI (DCICharacteristics), including at least one of the RNTI used to decode theDCI, the format of the decoded DCI (e.g., type 1, or type 2, etc.), thelocation of the CCE(s) of the decoded DCI (for example, in a specificsearch space and/or in a specific portion of said search space), theAggregation Level (AL) of the decoded DCI, the presence or absence of acarrier indication field (CIF) in the decoded DCI, the value of acarrier indication field (CIF) in the decoded DCI, the received powerlevel of the decoded DCI, the received coding gain of the decoded DCI,and the number of repetitions of the decoded DCI.

If a UE finds multiple reference DCIs for the same subframe, for exampleusing any of the means disclosed above, the UE may be configured to muteany ACK/NACK feedback corresponding to the particular subframe.Alternatively, the UE may be configured to select one of the multiplereference DCIs to use as the reference DCI for the subframe by selectingthe reference DCI randomly from among the multiple reference DCIs,selecting the DCI received on the PDCCH of a serving cell with aspecific index or priority (e.g., CC index/priority, DCI rx), selectingthe DCI corresponding to a PDSCH transmission of a serving cell with aspecific index or priority (e.g., CC index/priority, PDSCH tx), orselecting the DCI received with a specific characteristic (i.e., usingat least one of DCI Characteristics set forth above.)

If a UE fails to find any reference DCI for a given subframe, the UE maybe configured to implement another embodiment disclosed herein,including muting any ACK/NACK feedback corresponding to the subframe ortransmitting ACK/NACK feedback on a configured PUCCH resource.

In any of the embodiments discussed herein, a base station (e.g., aneNodeB) may transmit on PDCCH one or more DCI formats, each of which mayhave a higher probability of being successfully decoded by a UE thanother DCI(s) sent in the same sub-frame. The base station may transmitthis DCI in such a manner that the UE identifies it as a reference DCI.Where the base station transmits the DCI in a manner that would causethe UE to determine multiple reference DCIs, the base station may beconfigured to make decoding attempts for the HARQ ACK/NACK feedback fromthe UE on multiple PUCCH resources in the same sub-frame, eachcorresponding to a reference DCI.

With the DCI reference embodiments disclosed herein, given, for example,a 1% probability of a DCI being missed, the ACK/NACK HARQ feedback maybe muted relatively rarely. In these embodiments, the ACK/NACK HARQfeedback may only be muted when the reference DCI (or all of thereference DCIs) is missing in a given subframe, and not when a DCI thatis not used as a reference is missed.

Robustness may be introduced to a PUCCH resource indication method withthe introduction of redundancy between multiple DCIs the UE may receivein the same sub-frame. In an embodiment, at least some of theinformation present in a DCI among multiple DCIs associated with asubframe may be present in more than one of the multiple DCIs. A UE maydetermine a PUCCH ACK/NACK resource based on explicit signaling usingone or more of the disclosed embodiments. A UE may receive aconfiguration of one or more PUCCH ACK/NACK resources (i.e., a set ofresource(s)). In addition, a UE may successfully decode at least one DCI(e.g., for a PDSCH transmission) in a given subframe. In still anotherembodiment, a UE may determine, from a field of said DCI, which resourceto use based on at least one of an indication (e.g., an index) to aresource from the set of configured resources, an indication todetermine the resource based on said DCI (e.g., from the first CCE ofsaid DCI), and a configured priority based on an association between anindex of a resource in the set of resources and at least one of aserving cell (DL CC) on which at least one DCI was successfully decoded,a serving cell (DL CC) for which a DCI indicated a PDSCH transmission,and a DCI received with a specific characteristic (for example, at leastone of the DCI Characteristics set forth above.)

While embodiments disclosed herein may have been described withreference to a resource within a set of PUCCH ACK/NACK resources orequivalent terms, it should be understood that such embodiments may alsobe implemented where multiple sets of PUCCH ACK/NACK resources areconfigured and a UE instead determines which set of PUCCH ACK/NACKresources to use from among the multiple configured sets of PUCCHACK/NACK resources, including in embodiments where a UE uses atransmission method such as channel selection for HARQ ACK/NACKinformation bits, a transmission method using transmit diversity withSORTD (spatial orthogonal-resource transmit diversity) or a combinationthereof.

In an index-based allocation embodiment, a UE may not have to rely onone or more reference DCI(s). In such an embodiment, a base station maybe configured to include a 2-bit field in the DCI format(s)corresponding to control signaling to multiple CCs (either for all CCs,or a subset of all the CCs). This may be configured by higher layer suchas RRC. In this embodiment, all DCIs corresponding to said CC subset maycarry the same value for the 2-bit field. Thus, regardless of whetherone or more of the DCI may be lost, as long as one is successfullydecoded at the UE, the UE may still have the means to transmit feedback.The UE may interpret the 2-bit field in a successfully decoded DCI is asfollows.

00: There is only 1 CC being scheduled—use a legacy method for PUCCHresource allocation (e.g., any other method that may be used in a singlecarrier environment), i.e., based on CCE position of said DCI.Alternatively, this code point may point to another PUCCH resourceconfigured by higher layers (PUCCH resource #0).

01: There is more than one assignment—use PUCCH resource #1 among set ofPUCCH resources configured by higher layers for multi-CC assignment.

02: There is more than one assignment—use PUCCH resource #2 among set ofPUCCH resources configured by higher layers for multi-CC assignment.

03: There is more than one assignment—Use PUCCH resource #3 among set ofPUCCH resources configured by higher layers for multi-CC assignment.

In the above embodiments, the field of the DCI indicating the PUCCHresource to use may correspond to an already existing field of the DCIformat used for DL assignments. In this case, the UE behavior may bere-defined with respect to the functionality originally associated withthis field. For instance, where the TPC (transmit power control) isreused, the transmission power adjustment applied by a UE upon receptionof at least one DCI containing a DL assignment may be a function of thecode point received for the field, or a subset of the bits thereof,according to a mapping that may be different from that used in case ofsingle-carrier operation. Alternatively, or in addition, thetransmission power adjustment applied by a UE upon reception of at leastone DCI containing a DL assignment may be a function of at least oneproperty of the DCI containing the DL assignment, such as (but notlimited to) the DL carrier from which the DCI is decoded, the searchspace from which the DCI is decoded, or the DL carrier to which theassignment applies. Alternatively, or in addition, the transmissionpower adjustment applied by a UE upon reception of at least one DCIcontaining a DL assignment may be a function of the set of code pointsreceived from the TPC fields of all or a subset of DCI containing DLassignments. For example, a certain power adjustment may be applied onlyin case all TPC fields from DCI containing DL assignments to a Scell (orany cell) have the same value. Alternatively, or in addition, thetransmission power adjustment applied by a UE upon reception of at leastone DCI containing a DL assignment may be a function of a pre-determinedvalue that may be set by higher layers, such as 0 dB (i.e., noadjustment.)

In an embodiment, a subset of code points of the reused TPC field may bereserved for the purpose of indicating a power adjustment and may notindicate a PUCCH resource. A UE receiving a DCI with the field set toone of these code points may only apply a power adjustment according toa mapping that is possibly different from the one used forsingle-carrier operation, and may not use the value of the field in thedetermination of the PUCCH resource(s) to use. The DCI may also notindicate any DL assignment, i.e., the UE may not attempt any PDSCHreception upon decoding of such DCI.

In a non-limiting example of reinterpretation of the TPC field, the TPCfield received in a DCI that contains an assignment for the DL primarycarrier (or Pcell) may be interpreted in the same way as the originalTPC field interpretation (for single-carrier operation), while the TPCfield received in a DCI that contains an assignment for the DL secondarycarrier (or Scell) may be reused for indicating a PUCCH resource(s)according to one of the above embodiments. In addition, one code pointof the TPC field of any DCI containing an assignment for a Scell mayrepresent, in addition to one or more PUCCH resources, a poweradjustment of pre-defined value (such as +3 dB.) The selection of thiscode point may allow the network to signal a power increase to a UE witha greater reliability because the command may be received even if theDCI containing the assignment to the Pcell is lost. The UE may apply thepower adjustment if it receives a DCI containing a DL assignment withthe TPC field set to this specific code point. Alternatively, the UE mayapply the power adjustment only if the TPC field is set to the specificcode point for all received DCIs containing a DL assignment for a Scell.

In an embodiment, if a UE transmits HARQ ACK/NACK information bits usinga transmission method such as channel selection, instead of selecting asingle resource from a single set of semi-statically configured PUCCHresources, the UE may instead select a set of PUCCH resources frommultiple sets of semi-statically configured PUCCH resources to be usedfor transmission using channel selection.

In an embodiment, if a UE transmits HARQ ACK/NACK information usingSORTD transmit diversity, a single resource indication received from aDCI may indicate a pair of PUCCH resources on which the UE maysimultaneously transmit to implement SORTD transmit diversity. This maybe applicable only to the case where the DCI is not received in theprimary carrier (Pcell).

In an embodiment, if a UE transmits ACK/NACK information using atransmission method based on channel selection and there are two HARQACK/NACK bits to report for a DL assignment, a single resourceindication received from a DCI may indicate two PUCCH resources wherethe selection of the resource on which to transmit is determined basedon the HARQ ACK/NACK bits to report according to the channel selectioncodebook. This may be applicable only to the case where the DCI is notreceived in the primary carrier (Pcell).

In an embodiment, if a UE transmits ACK/NACK information using atransmission method based on channel selection and SORTD transmitdiversity and there are two HARQ ACK/NACK bits to report for a DLassignment, a single resource indication received from a DCI mayindicate a set of two pairs of PUCCH resources (i.e., a total of 4resources), on each of which the UE may simultaneous transmit toimplement SORTD transmit diversity, and where the selection of the pairof PUCCH resources on which to transmit is determined based on the HARQACK/NACK bits to report according to the channel selection codebook.Alternatively, where the DCI containing such a DL assignment is receivedin the Pcell, two of the four required PUCCH resources may be indicatedin the DCI and the other two may be implicitly derived from the startingposition of the CCE (control channel element) where the DCI is decoded.The two resources implicitly derived may or may not belong to a samepair of resources.

Successfully decoded DCIs containing DL assignments may have the samevalues for the field indication regardless of the properties of theseDCIs. This approach is useful for schemes where a single PUCCH resource(or set of PUCCH resources) is needed to transmit the feedbackregardless of the number of HARQ ACK/NACK information bits. In the eventthat a UE successfully decodes DCIs for which field indication valuesdiffer in a given subframe, it may be that a network error or a falsedetection has occurred. To handle this situation, in an embodiment, a UEmay perform the actions associated with other embodiment disclosedherein, such as muting any ACK/NACK feedback corresponding to thesubframe or selecting one DCI for the purpose of interpreting the fieldindication and determining how to transmit ACK/NACK on PUCCH by usingone of a variety of means. Such means include randomly selecting any ofthe DC, selecting the DCI received on the PDCCH of a serving cell (CC)with a specific index or priority (CC index/priority, DCI rx), selectingthe DCI corresponding to a PDSCH transmission of a serving cell (CC)with a specific index or priority (CC index/priority, PDSCH tx),selecting the DCI received with a specific characteristic (e.g., atleast one of DCI Characteristics set forth above), excluding a DCI whosevalue differs from the value of more than one other decoded DCI in thesame subframe (e.g., in case of false PDCCH detection), and/or selectingthe DCI with an indication field whose value is similar to the one usedfor the previous ACK/NACK transmission on PUCCH.

In an embodiment, the interpretation of the field indicating the PUCCHresource may be different depending on at least one property of the DCIcontaining the DL assignment, such as the DL carrier from which the DCIis decoded or the DL carrier to which the assignment apply. Utilizing adifferent interpretation depending on the DL carrier to which theassignment may apply may be useful where some of the HARQ ACK/NACKfeedback is signaled through a channel selection scheme where multiplePUCCH resources must be indicated to the UE in a single subframe tobuild a channel selection codebook depending on the number or HARQACK/NACK feedback bits to transmit or the number of received DLassignments.

In an embodiment, a UE may determine an incorrect PDCCH reception,either by determining that a PDCCH has been missed or determining that afalse positive has been detected (i.e., confirmation of receipt of aPDCCH that was not actually received.) If a UE determines it has neithermissed a PDCCH nor decoded a false positive (e.g., the number ofsuccessfully decoded DCI(s) equals the value in each of decoded DCI), itmay transmit the corresponding HARQ ACK/NACK feedback according to themethod it normally uses (e.g., any of the methods described in thisdocument). However, upon determining a missed PDCCH or a false positive,the UE may be configured to take one or more of several actions.

In an embodiment, a UE may be configured to perform muting, where the UEmay mute, or otherwise not transmit, any ACK/NACK feedback correspondingto the associated subframe. Muting may be performed when the UE cannotdetermine a reference DCI and/or if the UE does not have asemi-statically allocated PUCCH resource for ACK/NACK transmission. Insuch embodiments, the UE may mute feedback for the correspondingsubframe. This may result in the network detecting DTX on PUCCH, whichmay in turn be interpreted by the network as an indication that the UEmay have incorrectly decoded the PDCCH for the corresponding subframe.

In a further embodiment, the UE may perform an LTE R10 allocation wherethe UE may transmit ACK/NACK feedback by selecting a semi-staticallyconfigured PUCCH resource, for example, an LTE R10 PUCCH resourceconfigured by RRC. If bundling for ACK/NACK is configured, the UE maydetermine that at least one transmission failed (e.g., a missed PDCCHmay imply a missed assignment) and transmit a bundled ACK/NACK value ofNACK on the selected PUCCH resource. In this embodiment, the network maynot detect that the UE may have incorrectly decoded the PDCCH for thecorresponding subframe.

In another embodiment, the UE may perform allocation by transmittingACK/NACK feedback by selecting a PUCCH resource according to the legacyor any other method that may be used in a single carrier environment fordynamic PUCCH allocation (i.e., as a function of the first CCE of a DCIused as a reference DCI.) If the UE has successfully decoded a DCI onthe PCell only, then that DCI may be used as the reference DCI. If thesuccessfully decoded DCI is for a PDSCH transmission (or controlsignaling, such as SPS) for the PCell (e.g., the DCI was decoded in theUE-specific search space corresponding to scheduling for the PCell), theDCI may be used as the reference DCI.

Alternatively, if bundling for HARQ ACK/NACK on PUCCH is configured, theUE may determine that at least one transmission has failed (e.g., amissed PDCCH may imply a missed assignment) and may transmit a bundledACK/NACK value of NACK on the selected PUCCH resource. In thisembodiment, the network may determine that the UE has incorrectlydecoded the PDCCH for the corresponding subframe based on detecting theresource on which it receives the PUCCH transmission. This may besimilar to embodiments where channel selection using a dynamic or asemi-static resource may be used to convey one bit of information.

In an embodiment, the UE may transmit ACK/NACK feedback by selecting onePUCCH resource from a set of multiple PUCCH resources, where thetransmission implicitly indicates that at least one PDCCH wasincorrectly decoded (e.g., that at least one PDCCH was missed.) In thisembodiment, the UE may use a method based on channel selection, wherethe selection of a PUCCH resource from a set of PUCCH resources providesan indication to the network that the UE missed at least one PDCCH. Thisembodiment may be used when one or more set(s) of PUCCH resources aresemi-statically configured by the network (e.g., RRC configuration.) Thenetwork may determine that the UE has incorrectly decoded the PDCCH forthe corresponding subframe based on detecting the resource in which itreceives the PUCCH transmission.

Alternatively, a UE may use a scrambling code where the UE may transmitACK/NACK feedback using a specific scrambling code applied to thetransmission of HARQ ACK/NACK information (e.g., on PUSCH, on LTE R8 orLTE R9 PUCCH, or on LTE R10 PUCCH.) The scrambling code may indicatethat at least one PDCCH was incorrectly decoded (e.g., at least onePDCCH was missed.) This scrambling code may include a set of codesproviding a binary indication of a missed PDCCH. Alternatively, thescrambling code may indicate the DCI(s) that were successfully decoded(e.g., for which PDSCH and/or for which CC control signaling wasdecoded.) This scrambling code may include a set of codes where eachcode provides a different code point. In this embodiment, the UE mayinterpret the different available code points based on the number ofconfigured DL SCCs in addition to the PCell, the number of active DLSCCs, and/or the number of PDSCH assignments received in the subframecorresponding to the HARQ ACK/NACK feedback information. In thesescrambling code embodiments, the network may determine that the UE hasincorrectly decoded the PDCCH for the corresponding subframe based ondetecting the scrambling code that was used by the UE to make the PUCCHtransmission.

In an embodiment, a UE may be configured to perform HARQ ACK/NACKbundling on PUCCH. If cross-carrier scheduling is not used, then a UEmay not always have a reference DCI for the purpose of selecting theproper PUCCH resource according to legacy or single carrier methods(i.e., the UE may not receive a DCI on the PDCCH of the primary servingcell, PCell, in every subframe for which it is expected to transmitfeedback on PUCCH.) If the UE is configured to use HARQ ACK/NACKbundling, the UE may determine which PUCCH allocation method to use todetermine the PUCCH resource for the transmission of ACK/NACK usingvarious means.

In an embodiment, the UE may determine whether cross-carrier schedulingis used in determining the PUCCH allocation method for transmittingACK/NACK feedback. In this embodiment, if cross-carrier scheduling isused, the UE may use a dynamic PUCCH allocation method based on the DCIwith the lowest (or highest) CCE index on the PDCCH used forcross-carrier scheduling (typically the PCell), the DCI applicable to atransmission (control signaling) on the PCell (if any), or a combinationof these two. In such embodiments, priority may be given to the DCI ofthe PCell (when present). If cross-carrier scheduling is not used, theUE may be configured to use a semi-static PUCCH allocation method.Alternatively, the semi-static PUCCH allocation method may be used onlyfor feedback related to a subframe in which DCI(s) and/or PDSCH(s) areonly received on one or more SCell(s), while a dynamic PUCCH allocationmethod may be used by the UE for any other subframe.

Alternatively, a UE may determine whether the UE has successfullydecoded at least one DCI on the PDCCH of the PCell and/or whether or notthis corresponds to a “DCI and/or PDSCH” applicable to the PCell inorder to determine the PUCCH allocation method for transmitting ACK/NACKfeedback. For example, if the UE can determine a reference DCI on thePCell, the UE may select the dynamic resource allocation method based onthe identified reference DCI. If the UE receives a DCI and/PDSCHapplicable to the PCell (i.e., the DCI was decoded in the UE-specificsearch space corresponding to the PCell), the UE may select the dynamicPUCCH allocation method based on the identified reference DCI.

In an embodiment, the UE may determine whether the UE has incorrectlydecoded at least one PDCCH in the subframe for which ACK/NACK feedbackis transmitted in order to determine the PUCCH allocation method fortransmitting ACK/NACK feedback. A UE may be configured with ACK/NACKbundling in combination with means for actions taken when the UEdetermines a missed PDCCH or false positive (as described above.) The UEmay transmit the ACK/NACK feedback on PUCCH using a resource that cancarry at least two bits of information (e.g., PUCCH format 1b), where afirst bit indicates ACK/NACK feedback applicable to a “DCI and/or PDSCH”applicable to the PCell (i.e., feedback is sent for transmissions on thePCell.) ACK/NACK for multiple codewords may be bundled in thisembodiment if spatial multiplexing is configured for the PCell. A secondbit may indicate the bundled value of the ACK/NACK feedback for at leastone SCell, and in one embodiment, for all transmissions received forSCells of the UE configuration in the corresponding subframe.

The UE may be configured to always transmit the ACK/NACK bits on asemi-statically configured resource. The UE may also, or instead, beconfigured to transmit the ACK/NACK bits on a semi-statically configuredresource only when the UE has not received a “DCI and/or PDSCH”applicable to the PCell, regardless of whether or not the UE hasdetected that it may have incorrectly decoded at least one DCI.Otherwise the UE may be configured to use a dynamic PUCCH allocationmethod. In still another variation, the UE may transmit the ACK/NACKfeedback on PUCCH by selecting the semi-static PUCCH allocation methodif it does not detect that it incorrectly decoded at least one DCI on aPDCCH (in an embodiment, only if no “DCI and/or PDSCH” applicable to thePCell was received) and selecting the dynamic PUCCH allocation methodotherwise.

In embodiments where static PUCCH ACK/NACK resources are used, a UE maybe configured to determine such resources using one or more of severalmethods. If a simple extension to LTE R8 or LTE R9 is used (i.e., aresource index is determined from the lowest numbered CCE of the firstDCI decoded by the UE, or determined from the lowest numbered CCEamongst all DCI decoded by the UE), there may a potential for acollision on the PUCCH resource. A first UE may receive its first DCI onCCE #N on serving cell 1 while a second UE may receive its first DCI onCCE #N on a different serving cell. With mapping analogous to what isdone for PUCCH 1/1a/1b where the resource index is given by n_(PUCCH)⁽¹⁾=n_(CCE)+N_(PUCCH) ⁽¹⁾, both UEs may select the same PUCCH resourceindex since only one UL CC will be used to carry PUCCH. In the eventthat a base station (e.g., an eNodeB) scheduled UE DCIs to avoid thisconflict, there may remain a possibility of collision in the case ofincorrect PDCCH reception if one of the UEs is not able to determinethat a detection has been missed.

In an embodiment, the offset N_(PUCCH) ⁽¹⁾ may be specified on a perserving cell basis, effectively partitioning the PUCCH space for type 1into M subspaces, where M is the number of serving cells. Each subspacemay be the same size, may be scaled appropriately to reflect thetransmission bandwidth of each serving cell, or may be sized based onsome other criteria. Upon selecting a particular DCI from which to takethe CCE number to calculate the index, the UE may utilize N_(PUCCH) ⁽¹⁾corresponding to the serving cell on which that DCI was received.Alternatively, M may be considered by the UE to be the number of activeserving cells. In such an embodiment, the number of active serving cellsmay include DL CCs where at least one of the serving cells has beenexplicitly activated using explicit control signaling (e.g., L1/PDCCHDCI, L2/MAC in a Control Element, or L3/RRC message.)

In an embodiment, a third PUCCH space may be created, for example,between the existing PUCCH format 1 and PUCCH format 2 spaces, and UEsconfigured for carrier aggregation may utilize this space. As a result,the per-serving cell offset may now be N_(PUCCH) ⁽³⁾, distinct from theLTE R9 and LTE R9 N_(PUCCH) ⁽¹⁾, and this N_(PUCCH) ⁽³⁾ may be used tocalculate the resource index.

In an embodiment, a UE may be configured to perform PUCCH resourceselection with a configured DL Semi-Persistent Scheduling (SPS). Suchconfiguration may result in a SPS transmissions in certain subframes,where a SPS transmission is a PDSCH transmission without a correspondingPDCCH (or DCI) transmission, e.g., in subframe n−4. In a subframe forwhich the UE is expected to transmit HARQ ACK/NACK feedback for aconfigured DL assignment (i.e., DL SPS), a UE configured formulticarrier operation may determine whether it should use the ACK/NACKPUCCH resource configured/activated for SPS or the PUCCH resourcecorresponding to the dynamic scheduling rules.

To determine the PUCCH resource to use, in an embodiment the UE may beconfigured to select the PUCCH resource according to the dynamicscheduling rules before selecting the resource configured/activated forthe HARQ ACK/NACK feedback for the SPS transmission. In this embodiment,the UE may be configured with at least one secondary serving cell, orScell, in addition to a first primary serving cell, or Pcell, and withat least one DL SPS assignment. The DL SPS assignment may be configuredfor the PDSCH of the first primary cell. In some embodiments, the UE mayhave one or more states corresponding to having at least one of theserving cell(s) of the UE activated (i.e., either implicitly, forexample based on timers, or explicitly, for example by FAC) and/orhaving at least one of the serving cell(s) of the UE is activated byFAC.

In such an embodiment, for a given subframe if the UE is expected totransmit HARQ ACK/NACK feedback for at least one PDSCH transmissioncorresponding to a configured assignment (e.g., SPS) and correspondingto a dynamically scheduled assignment in at least one serving cell, thenthe UE may be configured to select the PUCCH resource based on themultiple HARQ ACK/NACK transmission method (i.e., the UE may not use theconfigured PUCCH index reserved for a SPS assignment.) Otherwise, the UEmay be configured to use the PUCCH ACK/NACK transmission methodapplicable to the type of the received PDSCH transmission. This impliesin particular that in case the UE only receives an SPS assignment, i.e.a PDSCH transmission where there is not a corresponding PDCCH (or DCI)transmission (in subframe n−4 for FDD) in a primary cell, the UEdetermines the PUCCH index according to its higher layer configuration.In an embodiment, for any subframe for which the UE is configured asdescribed above (i.e., DL SPS with at least one secondary serving cell),the UE may be configured to select the PUCCH resource based on themultiple ACK/NACK transmission method (i.e., the UE may not make use ofthe configured PUCCH index for the SPS, if any.)

In an embodiment, a UE may be configured to multiplex HARQ ACK/NACK orDTX and SR on PUCCH. The UE may be configured with a PUCCH resource forSR. If the transmission of HARQ ACK/NACK on PUCCH coincides for a givensubframe with the transmission of a SR, the UE may transmit the positiveSR indication on the PUCCH resource configured for SR, and may mute theHARQ ACK/NACK or DTX information (utilizing, for example, PUCCH format1.) Alternatively, the UE may transmit M bits (M=1 or M=2) of HARQACK/NACK or DTX information using PUCCH format 1a (M=1 signaledinformation bit) or PUCCH format 1b (M=2 signaled information bits.) Thesignaled information bit(s) may be derived by the UE bundling ACK/NACKin the spatial domain for each DL carrier. For example, the UE mayperform the logical AND operation for the ACK/NACK of each codeword ifspatial multiplexing is configured. This may result in at most oneACK/NACK bit per serving cell for which at least one “DCI and/or PDSCH”is applicable. If no assignment is detected for a serving cell, the UEmay either set the corresponding bit to the same value as for NACK, ornot assign any bit of the sequence b(0) . . . b(N) to report feedbackfor this carrier. In this embodiment, one of the code points (forinstance, b(0)=b(1)=0) may be reserved to indicate that the UE detectedthat at least one DL assignment has been missed, for example, using oneor more embodiments as described herein. Bundling across carriers mayalso be used, resulting in a single ACK/NACK bit.

In an embodiment, the UE may truncate the series of ACK/NACK bits (orbundled ACK/NACK bits, for example according to the embodiment above)b(0) . . . b(N) to M bits. In this embodiment, bits corresponding to DCIand/or PDSCH of SCell(s) may be truncated (in an embodiment, all suchbits.) Alternatively, bits corresponding to DCI(s) decoded on the PDCCHof a SCell may be truncated (in an embodiment, all such bits.) In anembodiment, bits not corresponding to the first successfully decoded DCImay be truncated. In a variation of this embodiment, bits notcorresponding to the DCI with the lowest CCE and/or highest aggregationlevel may be truncated.

The M bits of HARQ information may be transmitted by the UE using aunique PUCCH resource configured for (in an embodiment, positive) SRtransmission. Alternatively, or in addition, the M bits of HARQinformation may be transmitted by the UE using one of a set of 2^(K)PUCCH resources configured for (in an embodiment, positive) SRtransmission. The PUCCH resource may be selected from the set of 2^(K)PUCCH by selecting a first PUCCH resource when the UE has detected thatat least one DL assignment has been missed (e.g., using one or moreembodiments disclosed herein) and a second PUCCH resource when the UEhas not detected that at least one DL assignment has been missed.Alternatively, the PUCCH resource may be selected from the set of 2^(K)PUCCH by selecting a PUCCH resource based on the value of K bits c(0) .. . c(K−1) obtained from the reception status (HARQ ACK/NACK and/or DTX)of a subset of carriers. For example, the values of c(0) . . . c(K−1)may correspond to the HARQ ACK/NACK information of carriers for whichfeedback was not transmitted in the b(0) . . . b(M) bits.

In an embodiment, the PUCCH resources to be used may be obtained in achannel selection method. The total number of PUCCH resources M requiredto support the channel selection scheme may be calculated based on atleast one of the transmission mode of each downlink carrier configuredfor PDSCH reception (equivalently, the number of codewords that can bereceived from each downlink carrier), the number of downlink carriersconfigured for PDSCH reception, the total number of codewords (C) thatmay be received from all downlink carriers configured for PDSCHreception, the total number of codewords that may be received from alldownlink carriers that may eventually configured for PDSCH reception,whether the UE is configured for full feedback or limited feedback(e.g., bundling) operation, whether feedback for a codeword or carrieris the same between NACK and DTX, whether a positive or negativescheduling request (SR) may be indicated along with the reception statusof each carrier/codeword, and whether the UE may report that it hasmissed some PDCCH assignments.

More specifically, in “full feedback” embodiments, the UE may have thecapability of reporting ACK or NACK/DTX status for each codeword. Thus,the channel selection scheme may enable the reporting of at least 2Cstates. The corresponding number of bits to feedback may be C. Assumingthat B bits may be conveyed by modulating the selected resource (e.g.,B=2 for PUCCH format 1b), the number of PUCCH resources M may be givenby M=2(C−B). Table 13 below illustrates some non-limiting examples whereB=2.

TABLE 13 Example codeword and PUCCH resource quantities TotalConfiguration Total number of (MIMO means 2 codewords, number of PUCCHSIMO means 1 codeword) codewords resources M CC1: MIMO + CC2: MIMO 4 4CC1: MIMO + CC2: SIMO 3 2 CC1: MIMO + CC2: SIMO + CC3: SIMO 4 4 CC1:SIMO + CC2: SIMO 2 1 CC1: SIMO + CC2: SIMO + CC3: SIMO 3 2 CC1; SIMO +CC2: SIMO + CC3: SIMO + 4 4 CC4: SIMO

It should be noted that a higher (or lower) number of PUCCH resourcesmay be necessary where the HARQ feedback codebook is designed such thatmore (less) than 2C states are reported.

Once the number of PUCCH resources M is obtained using one of thedisclosed embodiments, the UE may derives M^(IMP) PUCCH resources, whereM^(IMP) may be calculated as either the umber of downlink carriers forwhich PDCCH is configured to be received in a primary DL carrier a fixedvalue, such as 1 or 0.

The pth (0<p<=M^(IMP)−1) PUCCH resource (n⁽¹⁾ _(PUCCH,p)) to use in agiven subframe may be determined based on the number n_(CCE,p) of thefirst control channel element (CCE) used for transmission of the DCIassignment in the primary carrier corresponding to a PDSCH transmission(or downlink SPS release) in the pth downlink carrier in subframe n−k(k=4 for FDD). For instance, n⁽¹⁾ _(PUCCH,p) may be set ton_(CCE,p)+N⁽¹⁾ _(PUCCH) where N⁽¹⁾ _(PUCCH) is configured by higherlayers. Alternatively, the pth PUCCH resource to use in a given subframemay be determined based on the number n_(CCE,p) of the first controlchannel element (CCE) used for transmission of the pth detected DCIassignment in the primary carrier corresponding to a PDSCH transmission(or downlink SPS release) in any downlink carrier in subframe n−k (k=4for FDD), in which case the PUCCH resources may be ordered by resourceindex (increasing or decreasing) in the codebook.

n⁽¹⁾ _(PUCCH,p) may not be defined for a certain subframe due to theabsence of a corresponding DCI assignment. The codebook may be designedsuch that any code point indicating positive acknowledgment for acodeword received from a given carrier, but not from codewords receivedfrom other carriers, may only be mapped to a PUCCH resource that isderived from a DCI assignment corresponding to a transmission in thiscarrier.

The UE may also derives M^(EXP) PUCCH resources, whereM^(EXP)=M−M^(IMP), based on signaling from the physical layer (e.g.,from fields in the DCI assignment(s)), the MAC layer, the RRC layer, ora combination thereof. For instance, M^(EXP) PUCCH resources may beprovided from RRC signaling. Alternatively, an index to a specificsubset of M^(EXP) PUCCH resources may be provided in a DCI assignment,or in an activation/de-activation command (possibly at MAC layer), whilethe whole set of possible PUCCH resources may be provided from theconfiguration.

In an embodiment, various solutions may be used to resolve potentialuser multiplexing issues for uplink control when using PUCCH channelselection. When UCI is not large enough, a PUCCH container may be used.For example, for small to medium ACK/NACK payload sizes, PUCCH channelselection (CS) may be suitable. CS may provide better UE multiplexinggain due to its flexibility. CS may support up to nine UEs per RB,whereas other schemes may only support up to five UEs per RB. In somesystems, code division multiplexing (CDM)-based user multiplexing mayalready be in use for PUCCH. However, there may be issues associatedwith UE multiplexing for PUCCH channel selection.

In some LTE systems, there may be insufficient PUCCH resources for CSuser multiplexing. For example, for four ACK/NACK information bits(e.g., two CCs with MIMO), two PDCCHs may be transmitted, thus twoPUCCHs may be assigned to a given user. For CS in LTE R8, four PUCCHsare needed to indicate four ACK/NACK information bits or 16 states.Therefore, a method may be desired to assign PUCCHs to support CS usermultiplexing.

In some LTE systems, there may alternatively be over-sufficient PUCCHresources for user multiplexing. For example for four ACK/NACKinformation bits (e.g., four CCs with SIMO), four PDCCHs may betransmitted and thus four PUCCHs may be assigned to a given user. For CS(enhanced) only two PUCCHs may be needed to indicate four ACK/NACKinformation bits or 16 states. Assigning additional PUCCHs may reduceuser multiplexing gain and may increase overhead, and thus may not beresource utilization efficient. Therefore, a method may be desired toreassign PUCCH resource for enhanced user multiplexing.

In an embodiment, where there may be insufficient PUCCH resources for CSuser multiplexing, an offset may be applied to a PDCCH resource toassign or reserve additional PUCCH resources to support CS usermultiplexing. The offset may be with respect to the first CCE address ofthe given PDCCH (e.g., DCI.) For example, the first CCE address of thefirst PDCCH (e.g., DCI) may be used by a UE to assign or reserve a PUCCHresource (e.g., a first PUCCH) for a given UE and the offset to thefirst CCE address of the first PDCCH (e.g., DCI) may be used by the UEto assign or reserve an additional PUCCH resource (e.g., a third PUCCH)for the given UE. Similarly, the first CCE address of the second PDCCHmay be used by the UE to assign or reserve a PUCCH resource (e.g.,second PUCCH) for the given UE and the offset to the first CCE addressof the second PDCCH may be used by UE to assign or reserve an additionalPUCCH resource (e.g., fourth PUCCH) for the given UE, and so on. Theoffset may be of any value and may be configurable by a base station(e.g., an eNodeB) and/or a network.

Alternatively, a non-first CCE address (e.g., use the second or thirdCCE address, etc.) may be used to assign or reserve additional PUCCHresource for user multiplexing. In this embodiment, a second CCE addressof a PDCCH (e.g., DCI) may be used to indicate, assign or reserveadditional PUCCH resource, such as third and fourth PUCCH resources forUE. For example, the second CCE address of the first PDCCH (e.g., DCI)may be used by UE to indicate, assign or reserve the third PUCCHresource and the second CCE address of the second PDCCH may be used bythe UE to indicate, assign or reserve the fourth PUCCH resource, and soon. In an embodiment, a base station (e.g., an eNodeB) may schedulePDCCH (e.g., DCI) containing at least two CCEs (i.e., a second CCE maybe always scheduled or available to UE) when additional PUCCH resourceneeds to be indicated or assigned to UE. A UE may be configured to fallback to the embodiment above using one or more offsets when the secondCCE in a PDCCH (e.g., DCI) is not available or a PDCCH (e.g., DCI) withtwo or more CCEs is not scheduled.

In embodiments where there are over-sufficient PUCCH resources for usermultiplexing, the PUCCH resources that are not used may be re-assignedto some other UE. By doing so, additional UEs may be multiplexed at thesame time in the same PUCCH resource or RB and thus UE multiplexing gainmay be increased and/or overhead may be reduced. In such an embodiment,an offset may be applied to PUCCH resource assignments for users. Suchan offset may be used to align PUCCH resources for different users sothat multiple users may share the same PUCCH resource pool, therebyincreasing UE multiplexing gain and/or reduce overhead. In thisembodiment, different UEs may use different offset values to supportuser multiplexing. Offsets may be configured per UE or per group of UEson user-specific or user group-specific basis.

In this embodiment, each UE (or a group of UEs) may be configured to usea subset of PUCCH resource pool once PUCCH resource for multiple usersis aligned together in the same resource pool. Either or both the offset(to PUCCH resource) and subset (of PUCCH resource) may be configurableby a base stations, and either or both may be UE-specific. For example,PDCCH #1, 2, 3, and 4 may be transmitted for UE #1 and PDCCH #5, 6, 7,and 8 may be transmitted for UE #2. Originally UE #1 may be assigned byPUCCH resourced #1, 2, 3, and 4, which may be referred to as ResourceSet 1 or Resource Pool 1. UE #2 may be assigned by PUCCH resources #5,6, 7, and 8 which may be referred to as Resource Set 2 or Resource Pool2. To efficiently multiplex UEs, PUCCH at UE #1 may be re-routed usingoffset to Resource Set 2 or Resource Pool 2 (i.e., PUCCH resources #5,6, 7, and 8 from Resource Set 1 or Resource Pool 1.) A subset ofResource Set 2 or Resource Pool 2, say PUCCH resources #5 and 6 may beconfigured to UE #1 and the other subset of Resource Set 2 or ResourcePool 2 may be configured to UE #2, as an non-limiting example.

In another embodiment, a PUCCH resource may be remapped from a PDCCH CCEaddress. In such an embodiment, a PUCCH resource from PDCCH CCE addressmay be remapped to align the PUCCH resource of UEs to be in the same setor pool for supporting user multiplexing. In this embodiment, aPDCCH-to-PUCCH mapping rule may be modified to support CS usermultiplexing. Alternatively, an offset may be included in thePDCCH-to-PUCCH resource mapping function. UEs may use one or moredifferent resource subsets (or partitions) for user multiplexing,similar to the offset application to PUCCH resource assignments asdescribed above. In an example embodiment, PDCCH #1, 2, 3, and 4 may betransmitted for UE #1 and PDCCH #5, 6, 7, and 8 may be transmitted forUE #2. Originally UE #1 may be mapped to PUCCH resources #1, 2, 3, and 4and UE #2 may be mapped to PUCCH resources #5, 6, 7, 8. By re-mappingthe PUCCH resources for UEs, UE #2 may be re-mapped to PUCCH resources#1, 2, 3, and 4 from PUCCH resources #5, 6, 7, and 8, while UE #1 maystill use the same PUCCH resources #1, 2, 3, and 4. UE #1 may beassigned by PUCCH resource subset (e.g., PUCCH resources #1 and 2) andUE #2 may be assigned by another PUCCH resource subset (e.g., PUCCHresources #3 and 4.)

In an embodiment, when redundant PUCCH resources are available, theredundant PUCCH resources may be re-assigned to other UEs for increasinguser multiplexing gain as noted above. Alternatively, such redundantPUCCH resources may be used to support uplink transmission extension oruplink MIMO extension. Redundant PUCCH resources may be used forsupporting spatial orthogonal resource transmission at a UE when spatialorthogonal resource transmission is configured for such a UE.Alternatively, or in addition, a UE may use redundant PUCCH resourcesfor supporting spatial orthogonal resource transmit diversity (SORTD)when SORTD is configured for the UE. Alternatively, or in addition, a UEmay use redundant PUCCH resources for supporting spatial orthogonalresource spatial multiplexing (SORSM) when SORSM is configured for theUE. Alternatively, or in addition, a UE may use L-1 redundant PUCCHresources for SORTD (or SORSM, or the like) when SORTD (or SORSM, or thelike) is performed with L transmit antennas for a given UE. For example,when two transmit antenna SORTD is used, a UE may use one redundantPUCCH resource for supporting SORTD transmission and operation at theUE.

Several embodiments will now be described for performing resourcemapping for multiple ACK/NACK UL transmissions in carrier aggregationembodiments. These embodiments may allow a UE to determine the PUCCHresources that the UE may use to transmit HARQ ACK/NACK and other UCIand feedback. In an embodiment, using PUCCH transmission, multiple ULCCs may be used simultaneously for multiple PUCCH transmissions.Alternatively, one UL CC may be used for multiple PUCCH transmissions.

In embodiments where PUCCH is transmitted on a single UL componentcarrier (among one or multiple aggregated UL CC(s)), downlinkassignments for all serving cells may be transmitted on a single servingcell. In such an embodiment, for each PDSCH assignment on any servingcell, there may be a corresponding PDCCH transmission on a pre-specifiedserving cell. Thus, the ACK/NACK resource indices may implicitly beassociated with the lowest CCE index of PDCCHs without any complication.

In an embodiment, downlink assignments for multiple serving cells may betransmitted on multiple serving cells (i.e., cross-carrier scheduling.)In such an embodiment, if the same design criterion is followed forPUCCH resource mapping as may be used in LTE R8, the ACK/NACK resourceindices may not be uniquely associated with the CCEs of the PDCCHs inall the scheduled serving cells. Thus, cross-carrier mapping in LTE R10may require a solution to address any possible PUCCH resource indexcollision. In an embodiment, a different PUCCH resource offset valueN_(PUCCH) ⁽¹⁾ may be signaled for each serving cell. Different servingcells may be distinguished by different N_(PUCCH) ⁽¹⁾ values allowing aunique CCE-to-ACK/NACK index mapping in a serving cell in a similar wayas that used in LTE R8. In such implementations, since ACK/NACKresources corresponding to all serving cells would need to be reservedon a UL CC, the PUCCH overhead may be increased. Also, there may be aneed for additional higher layer signaling that is a function of thenumber of configured serving cells. Accordingly, for UEs with a largenumber of aggregated carriers, an increased overhead on higher layersignaling may occur.

While the embodiments described herein may provide means forcross-carrier PUCCH resource allocation/mapping, in some implementationsPUCCH may be transmitted on only one uplink component carrier in anasymmetric CC aggregation, whereas multiple PDCCHs may be simultaneouslytransmitted from different downlink CCs. Alternatively, multiple PUCCHsmay be transmitted on multiple uplink component carriers in anasymmetric CC aggregation, whereas DL carriers that transmit PDCCHs maybe more numerous than UL carriers that transmit PUCCHs. In suchembodiments, if multiple PDCCHs are transmitted on the same CCE indexn_(CCE) of their corresponding CCs, due to the implicit relationshipbetween the CCE index and the PUCCH format 1/1a/1b resource index,multiple DCI assignments may point to the same PUCCH HARQ ACK/NACKresource index n_(PUCCH) ⁽¹⁾, which may result in HARQ ACK/NACK resourcecollisions. Thus, the present disclosure sets forth some exemplaryresource mapping criterion that may be modified/extended according tothe disclosed embodiments to resolve this ambiguity among PUCCHresources.

In an embodiment, implicit cross-carrier mapping schemes may be used. InLTE-A FDD environments, when a UE uses PUCCH format 1/1a/1b resourcen_(PUCCH) ⁽¹⁾ for transmission of HARQ ACK/NACK, the UE may use one ofthe following disclosed methods for a PDSCH transmission indicated bythe detection of a corresponding PDCCH, or for a PDCCH indicatingdownlink Semi-Persistent Scheduling (SPS) release.

In such an embodiment, the PUCCH format 1/1a/1b resource may beimplicitly determined based on four parameters, two of which may be LTER8 parameters in order to maintain backward compatibility. Of theremaining two parameters, one may be configured by higher layersignaling and the other one may be determined through the correspondingDCI assignment. In such an embodiment, when a UE uses PUCCH format1/1a/1b resource n_(PUCCH) ⁽¹⁾ for transmission of ACK/NACK, the UE maybe configured to use the following mapping:n _(PUCCH) ⁽¹⁾ =N _(CC) n _(CCE) +N _(PUCCH) ⁽¹⁾ +n _(CI)where n_(CCE) may be the index of the first CCE used for transmission ofthe corresponding DCI assignment, N_(PUCCH) ⁽¹⁾ may be the number ofresources reserved for persistent PUCCH Format 1/1a/1b ACK/NACKsignaling, N_(CC) may denote the number of component carriers configuredby higher layers, and n_(CI) may be the index of the component carrierused for transmission of the corresponding DCI assignment.

The last two parameters described above, N_(CC) and n_(CI), may be basedon the LTE R10 3GPP standards in which there may be an asymmetriccarrier aggregation mode along with a three-bit control field known asCarrier Indicator (CI) to be incorporated into the PDCCH DCI formats.Note that in the case of only one carrier, where N_(CC)=1 and n_(CI)=0,the mapping formula of this embodiment may reduce to the mapping formulathat is specified by LTE R8.

FIG. 19 illustrates exemplary non-limiting PUCCH configuration 1900 thatmay be used in an embodiment for an exemplary system with five DL CCsand one UL CC. RBs 1910 represent resources that may be reserved fordynamic PUCCH format 1/1a/1b. Within RBs 1910, resources may be reservedfor each components carrier. For example, as illustrated in FIG. 19, RB1920 may be a resource reserved for CC 0, RB 1921 may be a resourcereserved for CC 1, RB 1922 may be a resource reserved for CC 2, RB 1923may be a resource reserved for CC 3, and RB 1924 may be a resourcereserved for CC 4.

In an example implementation of this embodiment, a UE may receive PDSCHtransmissions from five DL carriers in a subframe and may be configuredto feedback multiple ACK/NACKs associated with the different TransportBlocks (TBs) using only one UL component carrier. The parameter set forthis example system may be given as: N_(RB) ^(DL)=6, N_(SC) ^(RB)=12,N_(CC)=5, N_(PUCCH) ⁽¹⁾=0, n_(CCE)∈{0, 1, . . . , 5}. In thisembodiment, the PUCCH format 1/1a/1b resource indices n_(PUCCH) ⁽¹⁾corresponding to all DCI assignments may be calculated based on theabove-described mapping, as shown in Table 14.

TABLE 14 Dynamic PUCCH Format 1/1a/1b resource n_(PUCCH) ⁽¹⁾ usingn_(PUCCH) ⁽¹⁾ = N_(CC)n_(CCE) + N_(PUCCH) ⁽¹⁾ + n_(CI) mapping n_(CCE) =0 n_(CCE) = 1 n_(CCE) = 2 n_(CCE) = 3 n_(CCE) = 4 n_(CCE) = 5 Component0 5 10 15 20 25 Carrier 0 Component 1 6 11 16 21 26 Carrier 1 Component2 7 12 17 22 27 Carrier 2 Component 3 8 13 18 23 28 Carrier 3 Component4 9 14 19 24 29 Carrier 4

In an embodiment, the following mapping may be used for mapping PDCCHCCE index to PUCCH form at 1/1a/1b resource n_(PUCCH) ⁽¹⁾ fortransmission of ACK/NACK:n _(PUCCH) ⁽¹⁾ =N _(CC,group) n _(CCE) +N _(PUCCH) ⁽¹⁾ +f(n _(CI))where N_(CC,group) may denote the number of component carriers for theDL carrier group that pairs or associates with the UL carriertransmitting PUCCH, n_(CI) may be the index of the component carrierused for transmission of the corresponding DCI assignment, f(n_(CI)) maybe the mapping function that maps n_(CI) to index for the correspondingDL carrier group, and the parameters n_(CCE) and N_(PUCCH) ⁽¹⁾ may be asdefined elsewhere herein, namely n_(CCE) may be the index of the firstCCE used for transmission of the corresponding DCI assignment andN_(PUCCH) ⁽¹⁾ may be the number of resources reserved for persistentPUCCH format 1/1a/1b ACK/NACK signaling.

In an embodiment, when a UE uses PUCCH format 1/1a/1b resource n_(PUCCH)⁽¹⁾ for transmission of ACK/NACK, the UE may use the following mapping:n _(PUCCH) ⁽¹⁾=(N _(CC) −n _(CI)−1)×N _(p) n _(CI) ×N _(p+1) +n _(CCE)+N _(PUCCH) ⁽¹⁾where n_(CCE) may be the index of the first CCE used for transmission ofthe corresponding DCI assignment, N_(PUCCH) ⁽¹⁾ may be the number ofresources reserved for persistent PUCCH format 1/1a/1b ACK/NACKsignaling, N_(CC) may denote the number of component carriers configuredby higher layers, n_(CI) may be the index of the component carrier usedfor transmission of the corresponding DCI assignment, and p may beselected from {0, 1, 2, 3, 4} such that N_(p)≥n_(CCE)<N_(p+1) andN_(p)=max {0,└(N_(RB) ^(DL)×(N_(SC) ^(RB)×p−5))/36┘}. N_(RB) ^(DL) maydenote the number of configured downlink RBs and N may denote the numberof subcarriers within a RB.

In an example implementation of this embodiment, using the same exampleconfiguration as described above, a UE may receive PDSCH transmissionsfrom five DL carriers in a subframe and may be configured to feedbackmultiple ACK/NACKs associated with the different Transport Blocks (TBs)using only one UL component carrier. The parameter set for this examplesystem may be the same as the example above: N_(RB) ^(DL)=6, N_(SC)^(RB)=12, N_(CC)=5, N_(PUCCH) ⁽¹⁾=0, n_(CCE) ∈{0, 1, . . . , 5}. In thisembodiment, the PUCCH format 1/1a/1b resource indices n_(PUCCH) ⁽¹⁾corresponding to all DCI assignments may be calculated based on theabove-described mapping, as shown in Table 15.

TABLE 15 Dynamic PUCCH Format 1/1a/1b resource n_(PUCCH) ⁽¹⁾ usingn_(PUCCH) ⁽¹⁾ = (N_(CC) − n_(CI) − 1) × N_(p) + n_(CI) × N_(p+1) +n_(CCE) + N_(PUCCH) ⁽¹⁾ mapping n_(CCE) = 0 n_(CCE) = 1 n_(CCE) = 2n_(CCE) = 3 n_(CCE) = 4 n_(CCE) = 5 Component 0 5 6 15 16 25 Carrier 0Component 1 7 8 17 18 27 Carrier 1 Component 2 9 10 19 20 29 Carrier 2Component 3 11 12 21 22 31 Carrier 3 Component 4 13 14 23 24 33 Carrier4

In an embodiment, the Demodulation Reference Signals (DM RS) associatedwith transmission of PUCCH may be derived from Zadoff-Chu sequences.These sequences may then be cyclically shifted and used to multiplexreference signals from different UEs within a cell (i.e., a CC.)However, the cyclic shift for each DM RS may be a function of both PUCCHformat and the corresponding resource index n_(PUCCH) ⁽¹⁾. Thus, thePUCCH format 1/1a/1b resource indices derived based on the mappingformulae set forth above may indirectly affect the amount of cyclicshift in each DM RS.

Note that the above-described mapping formulae may not requireadditional dedicated higher-layer signaling, but may instead exploit ahigher layer parameter that may be a part of the system configurationfor an LTE R10 system or implementation. In other words, it may be avalid assumption that the number of CCs would be a part of higher-layersignaling in LTE-A. Similarly, from a physical layer perspective, crosscarrier scheduling through a carrier indicator control field may besupported through the extension of the legacy or single carrier DCIformats. Therefore, the mapping formulae set forth above may not needany additional dedicated physical-layer control signaling.

In embodiments where there is not a corresponding PDCCH for a PDSCHtransmission in any downlink component carrier, such as downlinkSemi-Persistent Scheduling, the value of n_(PUCCH) ⁽¹⁾ may be determinedaccording to higher layer configuration.

Presented now are systems, means, and methods for transmitting HARQfeedback (e.g., ACK/NACK) for multiple carriers over PUCCH. Usingcarrier aggregation, for example in LTE-A, an uplink feedback payloadmay scale linearly with the number of configured/activated CCs. A singleUE-specific UL CC may be configured semi-statically for carrying PUCCHACK/NACK, scheduling request (SR), and periodic channel stateinformation (CSI) from a UE. An ACK/NACK multiplexing scheme based onthe DFT-S-OFDM may be used to support large ACK/NACK payload sizes, butsuch embodiments may have challenges associated with such a scheme whenthey are used for uplink feedback transmissions.

In user multiplexing embodiments, based on the DFT-S-OFDM structure, theHARQ ACK/NACKs and/or CSI from multiple UEs may be multiplexed into asingle PUCCH resource block using orthogonal Code Division Multiplexing(CDM). In such embodiments, it may be desirable to assure orthogonalityamong the UEs multiplexed into the single PUCCH RB, implicitly identifyPUCCH resource allocation at each UE, and/or randomize inter-cell andintra-cell interference.

In some embodiments that make use of DFT-S-OFDM, 24 quadraturephase-shift keying (QPSK) symbols may be transmitted, which may beequivalent to 48 encoded bits. Since the uplink feedback payload sizescales with the number of configured/activated CCs, it may be importantto design a variable channel coding scheme that provides a reasonablecoding gain over a range of payload sizes. In some embodiments, themaximum number of the HARQ ACK/NACK bits that may be transmitted undercarrier aggregation may be limited to 10-12 bits. Thus, the channelencoder may be optimized such that the performance targets related tothe ACK/NACK transmissions at low signal-to-interference ratios (SINRs)can be achieved. The payload size for CSI transmissions using carrieraggregation may be in the range of 20-55 bits, although other sizes,both larger and smaller, are contemplated. Accordingly, the channelencoder design for the CSI feedback signaling may be configured totarget reliable reception of large payloads.

The DFT-S-OFDM-based structure may be used to transmit the HARQ ACK/NACKand/or CSI on a single PUCCH RB. The physical mapping of feedbacksymbols on the available resource elements may impact the performance offeedback transmissions. One of the limitations that may arise related toACK/NACK mapping is that many current methods used in the art do notsufficiently exploit frequency diversity. With PUCCH transmissions,there may be no dimensioning of the corresponding resources with respectto the ACK/NACK and/or CSI payload. In embodiments set forth herein inmore detail, feedback symbols may be mapped on to the resource elementsof a single PUCCH RB such that the frequency diversity gain ismaximized, and ACK/NACK and CSI may be multiplexed on a single RB sothat specific performance targets may be met.

In an embodiment, the transmission of HARQ ACK/NACK and SRS may beconfigured to be in the same subframe. Handling such transmissions byDFT-S-OFDM-based structure may be accomplished by using a shortenedPUCCH transmission in such subframes as may be done in legacy or singlecarrier environments, where the last SC-FDMA symbol of the ACK/NACK maybe used for SRS transmission, and the same spreading factor may not beapplied on the data SC-FDMA symbols on both slots within a subframe.Alternatively, where extended cyclic prefix (CP) with five data SC-FDMAsymbols and one DM RS per slot is used, the structure of DFT-S-OFDM maybe different from the normal CP case. An extension of DFT-S-OFDM basedstructure to the subframes with extended CP may be implemented asdescribed herein.

The current disclosure also describes specific properties of atransmission using methods based on Channel Selection. In particular,one characteristic that is specific to such transmission(s) may be thatinformation bits encoded using Channel Selection (i.e., the b bits thatare conveyed by the detection of a transmission on one of N resources,where N=2b), may be more robustly decoded by a receiver than informationbit(s) obtained by decoding the received signal on the PUCCH resource.This may be because the detection of whether or not a signal on a PUCCHresource is present (i.e., DTX detection) may be more accurate than thedecoding of the information bit(s) in the received signal once a signalis indeed detected.

In an embodiment, a processing structure for UL feedback may withDFT-S-OFDM may be used. In such an embodiment, a UE may generate controlinformation and feed such control information back to the network usingmethod 2000 of FIG. 20. At block 2005, control information, such as UCI,may be generated by the UE. At block 2010, a number of DL CCs (servingcells) may be determined or obtained, and CRC attachment (in anembodiment, as described in more detail below) may be performed. In anembodiment, at block 2010 input bits a₀, a₁, . . . , a_(A-1) may begenerated for using as input to a channel encoder. At block 2015,channel coding may be performed using Reed Muller encoding (in anembodiment, as described in more detail below.) Alternatively, at block2020 channel encoding may be performed using tail-biting convolutionalencoding (in an embodiment, as described in more detail below.) Ineither case (channel coding using RM or tail-biting convolutionalencoding), the output generated by the channel encoder used at block2015 or block 2020 may be a length 48 bit sequence that may be denotedby b₀, b₁, . . . , b₄₇, as described in more detail herein.

At block 2025 rate matching may be performed using any means. At block2030, the UE may employ a channel interleaver that may interleavechannels at the bit level or the symbol level, as described in moredetail herein. At block 2035, the UE may obtain or determine one or morecell identities and employ a scrambler to perform scrambling, in anembodiment, as described in more detail below. At block 2040, modulationmay be performed. At block 2045, sub-carrier slot level hopping may beperformed, in an embodiment, as described herein. In conjunction, a UEmay obtain or determine n_(oc) ^(cell)(n_(s), k), which may be acell-specific parameter that varies with a sub-carrier number k and aslot number n_(s), as described in more detail herein. At block 2050,resource mapping may be performed, in an embodiment, as describedherein. Note that the UE may feedback control information on PUCCH usingany or all of the blocks of method 2000 in combination with thetransmission of PUSCH.

Note that the activities and functions performed at any of the blocks ofmethod 2000, and at any of the blocks of any other method describedherein, may be performed independently or in conjunction with any numberof the other activities and functions of any other blocks of method 2000and/or any number of the other activities and functions of any otherblocks of any other method disclosed herein. The order of performance ofsuch activities and functions may be any order, and not necessarily theorder in which the associated blocks are presented in FIG. 20, any otherfigure, or as described herein. All such embodiments are contemplated aswithin the scope of the present disclosure.

In an embodiment, both reference signals and control signals of the UEsassigned to transmit on the same set of subcarriers may be fullyorthogonal. More specifically, the orthogonality among UEs may beachieved by using a combination of cyclic time shifts of the sameZadoff-Chu (ZC) base sequence on the DM-RS symbols and the time-domainorthogonal cover code on the DM-RS symbols. Orthogonality between DMRSsof different UEs occupying the same set of subcarriers resource block(RB) may be provided by using different cyclic time shifts of the sameZC base sequence. Orthogonality between DMRSs of different UEs occupyingthe same set of subcarriers or RB may also be provided by usingdifferent time-domain orthogonal cover-codes on the DMRSs. The length-2and length-3 orthogonal block spreading codes may be based onWalsh-Hadamard codes (see Table 16 below) or discrete Fourier transform(DFT) codes (see Table 17 below) generated from DFT matrices ofdifferent sizes, and may be used in conjunction with the DFT-S-OFDMbased PUCCH formats with 2 and 3 DMRS symbols (i.e., SF=5 and SF=3,respectively).

TABLE 16 Time-domain spreading sequence indices for DMRS symbols; SF = 5Timed-Domain Spreading code Walsh-Hadamard code index for RS symbols ofLength-2 0 [+1 +1] 1 [+1 −1]

TABLE 17 Time-domain spreading sequence indices for DMRS symbols; SF = 4Timed-Domain Spreading code index for DMRS symbols DFT code of Length-30 [+1 +1 +1] 1 [+1 e^(j2π/3) e^(j4π/3)] 2 [+1 e^(j4π/3) e^(j2π/3)]

Regarding the time-domain orthogonal spreading code on the data SC-FDMAsymbols, orthogonality between the UCIs of different UEs occupying thesame set of subcarriers or RB may be provided by using differenttime-domain orthogonal cover-codes on the data SC-FDMA symbols. Thelength-5, length-4, and length-3 orthogonal block spreading codes may bebased on Walsh-Hadamard codes or DFT codes (see Table 18 for annon-limiting example of length-5) generated from DFT matrix of differentsizes, and may be used in conjunction with the DFT-S-OFDM based PUCCHformats with spreading factors equal to 5, 4 and 3, respectively.

TABLE 18 Length-5 orthogonal spreading codes Timed-domain spreading codeindex for data symbols DFT code of length-5 0 [+1 +1 +1 +1 +1] 1 [+1e^(j2π/5) e^(j4π/5) e^(j6π/5) e^(j8π/5)] 2 [+1 e^(j4π/5) e^(j8π/5)e^(j2π/5) e^(j6π/5)] 3 [+1 e^(j6π/5) e^(j2π/5) e^(j8π/5) e^(j4π/5)] 4[+1 e^(j8π/5) e^(j6π/5) e^(j4π/5) e^(j2π/5)]

In an embodiment, for a DFT-S-OFDM based PUCCH transmission with normalCP and spreading factor of five, the UE may use a different cyclictime-shift of length-12 ZC-based sequence for frequency-domain spreadingfor each DM RS symbol within a slot, a length-2 orthogonal blockspreading code for DMRS time-domain spreading on the two availablereference SC-FDMA symbols in each slot, and/or a length-5 orthogonalblock spreading code for data time-domain block spreading on the fiveavailable data SC-FDMA symbols in each slot.

Various methods may be employed to identify resource allocation at a UE.In the case of semi-persistently scheduled downlink data transmissionson the PDSCH without a corresponding downlink grant on the PDCCH, and/ordynamically scheduled downlink data transmissions on the PDSCH indicatedby downlink assignment signaling on the PDCCH, a UE may use the PUCCHACK/NACK resource index to determine the combination of the cyclic timeshift of the ZC-based sequence, α, and time-domain orthogonal codesassigned to the UE within a PUCCH region.

The PUCCH ACK/NACK resource index, n_(PUCCH) ⁽³⁾, which may be used bythe UE for transmission of a new PUCCH format (e.g., PUCCH format 3)could be either semi-statically configured by higher layer signaling orimplicitly determined by the UE based on the index of the first ControlChannel Element (CCE) of the downlink control assignment on the DL PCC.The UE may determine, using information from the identified PUCCHresource index, the cyclic shift for reference signals or DMRSα(n_(s),l), the orthogonal sequence index for block-wise spreading ofdata signals n_(oc)(n_(s), k), and the orthogonal sequence index forreference signals or DMRS m_(oc)(n_(s)). Here, n_(s) may be the slotnumber within the radio frame, l may be the index of the referencesymbol within the slot, and k may be the index of the subcarrier withinthe RB on which PUCCH is being transmitted.

In such an embodiment, the UE may determine the resource index withinthe two resource blocks of a subframe to which the PUCCH is mappedaccording to:m _(oc)(n _(s))=n _(PUCCH) ⁽³⁾ mod cwhere c may be the number of the DM RS symbols within a slot, andn _(oc)(n _(s) ,k)=n′(n _(s))wheren′(n _(s))=n _(PUCCH) ⁽³⁾ mod N _(SF) ^(PUCCH)with N_(SF) ^(PUCCH) as the spreading factor of the DFT-S-OFDM for datablock spreading and “mod” is the modulo operation. For example, theassigned time-domain orthogonal cover-code can be obtained as modulo-5and modulo-3 of the PUCCH resource index for a DFT-S-OFDM basedstructure with spreading factor of 5 and 3, respectively. Where the samedata block spreading code is used for both slots within a subframe(i.e., slot level hopping is disabled) and the same data block spreadingcode is used for all subcarriers within a slot (i.e., subcarrier-levelhopping is disabled), the index of the time-domain orthogonal cover-codemay be identified as:n _(oc) =n _(PUCCH) ⁽³⁾ mod N _(SF) ^(PUCCH)

In these embodiments, by introducing the time domain cover code for theRS symbols in each slot of the PUCCH in addition to cyclic shifts,another multiplexing dimension may be created. The examples of the PUCCHresource index allocation used by the UE within a PUCCH RB in theabsence of time-domain cover code for the RS symbols for Δ_(shift)^(PUCCH)=2 and Δ_(shift) ^(PUCCH)=3 are illustrated in Table 19 andTable 20, respectively. In this exemplary embodiment, the time domaincover code may not be applied on the RS symbols and the UE may derivethe cyclic shift for reference signals on the pth transmit antenna andlth SC-FDMA symbol, α_(p)(n_(s),l), for PUCCH format 3 according to:α_(p)(n _(s) ,l)=2π·n _(cs) ^((p))(n _(s) ,l)/N _(sc) ^(RB)where N_(sc) ^(RB) denotes the number of subcarriers within an RB andn _(cs) ^((p))(n _(s) ,l)=(n _(cs) ^(cell)(n _(s) ,l)+n′ _(p)(n_(s))Δ_(shift) ^(PUCCH))mod N _(sc) ^(RB)with n_(cs) ^((p))(n_(s),l) as a cell-specific parameter that varieswith the symbol number l and the slot number n_(s) and

${n_{p}^{\prime}\left( n_{s} \right)} = \left\{ {{\begin{matrix}{n^{\prime}\left( n_{s} \right)} & {{{if}\mspace{14mu} p} = 0} \\{\left( {{n^{\prime}\left( n_{s} \right)} + p} \right){mod}\mspace{11mu} N_{SF}^{PUCCH}} & {otherwise}\end{matrix}\mspace{14mu}{and}{n^{\prime}\left( n_{s} \right)}} = {n_{PUCCH}^{(3)}{mod}\mspace{11mu} N_{SF}^{PUCCH}}} \right.$for n_(s) mod 2=0 and byn′(n _(s))=└N _(SF) ^(PUCCH)(n′(n _(s)−1)+1)┘ mod(N _(SF) ^(PUCCH)+1)−1for n_(s) mod 2=1.

In an embodiment, the UE may identify the orthogonal sequence indexn_(oc)(n_(s)) at slot number n_(s) using the assigned resource indexn_(PUCCH) ⁽³⁾ for transmission of PUCCH format 3 according to:n _(oc)(n _(s))=└n′(n _(s))/Δ_(shift) ^(PUCCH)┘wheren′(n _(s))=n _(PUCCH) ⁽³⁾ mod N _(sc) ^(RB)for n_(s) mod 2=0 and byn′(n _(s))=└N _(sc) ^(RB)(n′(n _(s)−1)+1)┘ mod(N _(sc) ^(RB)+1)−1for n_(s) mod 2=1.

The cyclic shift of the demodulation reference signal on the pthtransmit antenna α_(p)(n_(s),l) for PUCCH format 3 may be given by:α_(p)(n _(s) ,l)=2π·n _(cs) ^((p))(n _(s) ,l)/N _(sc) ^(RB)wheren _(cs) ^((p))(n _(s) ,l)=(n _(cs) ^(cell)(n _(s) ,l)+n′ _(p)(n_(s)))mod N _(sc) ^(RB)with

${n_{p}^{\prime}\left( n_{s} \right)} = \left\{ \begin{matrix}{n^{\prime}\left( n_{s} \right)} & {{{if}\mspace{14mu} p} = 0} \\{\left( {{n^{\prime}\left( n_{s} \right)} + p} \right){mod}\mspace{11mu} N_{sc}^{RB}} & {otherwise}\end{matrix} \right.$

TABLE 19 Resource index used by the UE in the absence of cover-code onthe DMRS symbols for Δ_(shift) ^(PUCCH) = 2 Time-domain orthogonal codeindex for data block spreading with SF = 5 Cyclic shift index n_(oc) = 0n_(oc) = 1 n_(oc) = 2 n_(oc) = 3 n_(oc) = 4 0 UE 0 1 2 UE 1 3 4 UE 2 5 6UE 3 7 8 UE 4 9 10 11

TABLE 20 Resource index used by the UE in the absence of cover-code onthe DMRS symbols for Δ_(shift) ^(PUCCH) = 3 Time-domain orthogonal codeindex for data block spreading with SF = 5 Cyclic shift index n_(oc) = 0n_(oc) = 1 n_(oc) = 2 n_(oc) = 3 n_(oc) = 4 0 UE 0 1 2 3 UE 1 4 5 6 UE 27 8 9 UE 3 10 11

Note that in the case of Δ_(shift) ^(PUCCH)=3, up to four UEs may bemultiplexed on the same RB for SF=5, while in the case of Δ_(shift)^(PUCCH)=2, up to five UEs may be multiplexed on a single RB. However,in embodiments where the orthogonal cover code may be applied to thereference signals or DMRS, the maximum number of the UEs that may bemultiplexed on the same RB may be upper-bounded by the spreading factorof the orthogonal block code used for spreading of control informationon the data symbols (i.e., for SF=5, up to five UEs may always bemultiplexed on the same RB regardless of Δ_(shift) ^(PUCCH).)

Non-limiting examples of the PUCCH resource index allocation used by aUE within a PUCCH RB in the case of orthogonal cover code applied to thereference signals or DMRS are illustrated in Table 21.

TABLE 21 Resource index used by a UE in the presence of cover-code onthe DMRS symbols Orthogonal cover-code index for 2 DMRS Time-domainorthogonal code index symbols for data block spreading with SF = 5Cyclic shift index m_(oc) = 0 m_(oc) = 1 n_(oc) = 0 n_(oc) = 1 n_(oc) =2 n_(oc) = 3 n_(oc) = 4 0 UE 0 UE 0 1 2 UE 3 UE 3 3 4 UE 1 UE 1 5 6 UE 4UE 4 7 8 UE 2 UE 2 9 10 11

In an embodiment, the UE determines the physical resource blocks to beused for transmission of PUCCH format 3 in slot n_(s) as

$n_{PRB} = \left\{ \begin{matrix}\left\lfloor \frac{m}{2} \right\rfloor & {{{if}\mspace{14mu}\left( {m + {n_{s}\mspace{11mu}{mod}\mspace{11mu} 2}} \right){mod}\mspace{11mu} 2} = 0} \\{N_{RB}^{UL} - 1 - \left\lfloor \frac{m}{2} \right\rfloor} & {{{if}\mspace{14mu}\left( {m + {n_{s}\mspace{11mu}{mod}\mspace{11mu} 2}} \right){mod}\mspace{11mu} 2} = 1}\end{matrix} \right.$where N_(RB) ^(UL) demotes the number of UL RBs and the variable m forPUCCH format 3 may be given bym=└n _(PUCCH) ⁽³⁾ /N _(SF,0) ^(PUCCH) ┘+N _(offset) ^(RB)where N_(SF,0) ^(PUCCH) is the length of the spreading code applied onthe first slot and N_(offset) ^(RB) is a non-negative integer number.Note that when N_(offset) ^(RB) is equal to zero, it may imply that theoutermost RBs within the PUCCH region are allocated for PUCCH format 3transmissions.

In such an embodiment, in order to achieve backward compatibility withLTE R8, the RBs assigned for PUCCH format 3 transmissions in LTE R10 andbeyond may be a subset of the RBs allocated for PUCCH format 2transmissions. In this embodiment, the UL PUCCH configuration may betransparent to any LTE R8 UEs and both LTE R8 and LTE R10 UEs maycoexist. However, the LTE R10 UEs may need to be configured by a higherlayer regarding the number of RBs allocated for PUCCH format 3transmissions. In an embodiment, a system parameter N_(RB) ⁽³⁾ may bedefined that is broadcast. This parameter may be dynamically adjusteddepending on the average number of active LTE R10 UEs that areconfigured to transmit on PUCCH format 3. Based on this approach thevariable m for PUCCH format 2 may given bym=└n _(PUCCH) ^((2,p)) /N _(sc) ^(RB) ┘+N _(RB) ⁽³⁾where n_(PUCCH) ^((2,p)) may be a resource index provided by higherlayer for transmission of PUCCH formats 2/2a/2b on antenna port p. Alsonote that if N_(RB) ⁽³⁾ was not provided by higher layer (i.e., the UEis not configured to transmit on PUCCH format 3), the UE may assume thatN_(RB) ⁽³⁾=0.

In an exemplary embodiment, both n_(PUCCH) ⁽³⁾ and N_(RB) ⁽³⁾ parametersmay be signaled by defining two additional configuration parameters inthe IE PUCCH-Config of LTE R8 as follows:

PUCCH-ConfigCommon_r10 ::= SEQUENCE { deltaPUCCH-Shift ENUMERATED {ds1,ds2, ds3}, nRB-CQI INTEGER (0..98), nRB-PUCCH3 INTEGER (0..98), nCS-ANINTEGER (0..7), n1PUCCH-AN INTEGER (0..2047) n3PUCCH-AN INTEGER (0..494)}

In an embodiment, various methods may be employed to randomizeinter-cell and intra-cell interference. In such embodiments, bothinter-cell and intra-cell interference randomizations for PUCCHtransmissions may be achieved through scrambling. Accordingly, in eachsubframe in the uplink, the UE may be configured to scramble the controlinformation encoded bits prior to modulation. The scrambling sequenceused may be derived as a function of the identity of the cell or cellID, where, in an embodiment using an identity of the cell to which theUE has an Radio Resource Control (RRC) connection, the UE may scramblethe control information using the PCI of the DL PCC of its multicarrierconfiguration. The identity of the cell or cell ID may one or more ofthe physical cell ID (PCI), from the synchronization signal of the cell(in an embodiment, the PCI of the DL Primary Component Carrier (PCC) ofthe UE's multicarrier configuration), the cell ID (i.e., cellIdentity)read on System Information Block type 1 (SIB1) that may uniquelyidentify a cell in the context of the Public Land Mobile Network (PLMN)(in an embodiment, from the SIB1 of the DL PCC of the UE's multicarrierconfiguration), and the evolved global cell ID (i.e., EGCI), which mayinclude both the PLMN ID and the cellIdentity.

In an embodiment, the scrambling sequence used may be derived as afunction of at least one or a combination of the subframe number withina radio frame, the UE identity (for example, a Radio Network TemporaryIdentifier (RNTI) of the UE such as the UE's C-RNTI), and the identityof the UL CC carrying PUCCH or UL primary CC (for example, one or moreof an identity explicitly configured by the network as part of the UE'sradio connection configuration, the absolute radio-frequency channelnumber (ARFCN) or evolved absolute radio-frequency channel number(EARFCN) (i.e., the uplink frequency) of the UL CC, and the value of theCarrier Indication Field (CIF) used for cross carrier scheduling carriedby PDCCH, in an embodiment, the CIF value corresponding to the DL CC (orserving cell) to which said UL CC is linked.) The scrambling sequencemay also be derived as a function of at least one or a combination ofthe number/identity of the activated DL CCs or serving cells, thenumber/identity of the configured DL CCs or serving cells, and theidentity of the DL CCs or serving cells (for example, at least one ofthe identity of the DL PCC paired with the UL PCC which carriers PUCCHand the identity of the DL Secondary Component Carrier (SCC)(s) orsecondary serving cell(s) to which the HARQ ACK/NAK feedbackcorresponds.)

In an embodiment, the scrambling sequence used may be derived as afunction of at least one or a combination of the number of DL PDSCHassignments received in the subframe for which HARQ feedback is beingtransmitted or reported (in an embodiment only including the dynamicallyscheduled PDSCH DL assignments), a value derived as a function of thePUCCH resource on which the UE transmits the UCI, a value explicitlyconfigured by the network as part of the UE's radio connectionconfiguration, a value explicitly configured by the network as part ofthe UE's DL/UL PCC re-configuration, a value derived from theposition(s) of one or a subset of DL assignment(s) in the PDCCH(s) ofone or a subset of serving cells, and an index provided by higher layer(e.g., via a configuration or activation command.)

In an embodiment, a cell-specific hopping scheme based on apredetermined hopping pattern may be used to achieve inter-cellinterference randomization for DFT-S-OFDM based PUCCH transmissions. Thehopping may be performed on the sub-carrier level where, for a givensubcarrier in a given slot, the UE may use a different time-domainorthogonal cover codes for data block spreading. In such an embodiment,the time-domain orthogonal cover code index on a given subcarrier may beobtained by adding (modulo-N_(SF) ^(PUCCH)) a pseudo-randomcell-specific offset to the assigned time-domain orthogonal cover codeindex. In other words, the UE may determine the resource index withinthe two resource blocks of a subframe to which the PUCCH is mappedaccording ton _(oc)(n _(s) ,k)=(n _(oc) ^(cell)(n _(s) ,k)+n′(n _(s)))mod N _(SF)^(PUCCH)where n_(oc) ^(cell)(n_(s),k) may be a cell-specific parameter thatvaries with the subcarrier number k and the slot number n_(s). Forexample, for a DFT-S-OFDM based structure with spreading factor of 5 and3, the time-domain orthogonal cover code index on a given subcarrier ineven slots may be obtained by adding (modulo-5) and (modulo-3) apseudo-random cell-specific offset to the assigned time-domainorthogonal cover code index, respectively.

In an embodiment, parameter n_(oc) ^(cell) (n_(s),k) for N_(SF)^(PUCCH)=5 may be given by:n _(oc) ^(cell)(n _(s) ,k)=Σ_(i=0) ⁴ c(5N _(sc) ^(RB) ·n_(s)+5k+i)·2^(i)where c(i) may be the pseudo-random sequence. The pseudo-random sequencegenerator may be initialized with c_(init)=N_(ID) ^(cell) at thebeginning of each radio frame. The pseudo-random sequence used fortime-domain orthogonal cover code hopping may be a length-31 Goldsequence generator or any other length Gold sequence generator.

In an embodiment, the interference between cells (i.e., CCs) and betweenUEs may be randomized through the use of a time-domain cover-coderemapping scheme that may be used by the UE in the second slot accordingto a predetermined UE-specific or cell-specific hopping pattern. Thehopping-in may be performed on the slot-level where, for a givensubcarrier in each slot, the UE may use a different time-domainorthogonal cover code. According to an embodiment, a UE may determinethe resource index within the two RBs of a subframe to which the PUCCHis mapped asn _(oc)(n _(s) ,k)=(n _(oc) ^(cell)(n _(s) ,k)+n′(n _(s)))mod N _(SF)^(PUCCH)wheren′(n _(s))=n _(PUCCH) ⁽³⁾ mod N _(SF) ^(PUCCH)for even slots (i.e. n_(s) mod 2=0) andn′(n _(s))=└N _(SF) ^(PUCCH)(n′(n _(s)−1)+1)┘ mod(N _(SF) ^(PUCCH)+1)−1for odd slots (i.e., n_(s) mod 2=1.)

According to an embodiment, the HARQ ACK/NACK information bits and theCSI bits may be jointly encoded prior to scrambling and modulation andmay then be transmitted on both slots of a PUCCH subframe. The payloadsizes for the HARQ ACK/NACK and the CSI transmissions may be differentand the channel coding rate may be variable depending on the number ofactivated or configured serving cells and/or transmission modes forwhich HARQ feedback or periodic CSI are to be transmitted. The channelencoder may be a block coding-type scheme such as punctured a (64, k)Reed-Muller (RM) code for a DFT-S-OFDM-based or similar structure withSF=5 or punctured (128, k) Reed-Muller code for DFT-S-OFDM basedstructure with SF=3.

In an example embodiment, where SF=5, a (48, A) block code that isderived from a punctured RM(64, k), or a circular repetition of RM(32,k), may be used where A may be the payload size of the UCI. The RMcode may be designed such that its codewords are a linear combination ofthe N basis sequences denoted M_(i,n), where N may be the maximum numberof PUCCH payload bits. Depending on whether or not DTX is signaled for aserving cell, the value of N may be between 10 and 12 bits for themaximum number of aggregated CCs (e.g., five serving cells.) The encodedbit sequence of length 48 at the output of the channel encoder may bedenoted by b₀, b₁, . . . , b₄₇ where

${b_{i} = {\sum\limits_{n = 0}^{A - 1}a_{n}}}{\cdot M_{i,n}}$i = 0, 1, …  , 47with a₀, a₁, . . . , a_(A-1) as the input bits to the channel encoder.Note that both addition and multiplication operations in the aboveformula may be performed in the vector-space domain, i.e.:1·1=1,0·1=0,1·0=0,0·0=0,1+1=0,0+1=1,1+0=1,0+0=0.

In an embodiment, joint coding may also, or instead, be applied across asingle slot rather than across the subframe. According to such anembodiment, the RM (32, k) encoded sequence may be repeated on bothslots for SF=5 (or a RM (64, k) encoded sequence may be repeated on bothslots for SF=3.) However, the joint coding across both slots maymaximize the maximum achievable frequency diversity gain for UCItransmissions on PUCCH.

Alternatively, the HARQ ACK/NACK information bits and the CSI bits maybe separately encoded using a different variable coding rate prior toscrambling and modulation and then transmitted on both slots of a PUCCHsubframe. In such an embodiment, the performance of various controlssignaling at the target levels may be maintained. In other words, thecoding rate adjustment of each individual channel encoder may be made inorder to achieve the desired bit error rate (BER) or block error rate(BLER) operation point for a given control feedback type given that thepayload sizes for the HARQ ACK/NACK and the CSI transmissions may bedifferent depending on the number of activated or configured servingcells and/or transmission modes needed to transmit HARQ feedback orperiodic CSI.

In embodiments having small payload sizes (e.g., two bits), the channelencoder may be a block coding-type scheme, such as simplex code with acircular rate matching into 48 or 96 coded bits depending on thespreading factor used for the DFT-S-OFDM based or similar structure.Alternatively, the channel encoder may be a tail-biting convolutionalcode which generates 48 and 96 coded bits at its output for theDFT-S-OFDM based structures with SF=5 and SF=3, respectively.

In an embodiment, an n-bit Cyclic Redundancy Check (CRC) may be computedbased on control information and attached, or otherwise concatenated, tothe feedback information bits prior to the channel coding for improvingerror detection. In such an embodiment, the CRC may be of a variablesize that may be adjusted based on the payload size of UCI or the typeof control signaling (e.g., the HARQ ACK/NACK or CSI.) A non-limitingexample of the CRC length is eight bits which may be used to achieve amiss detection rate of 0.4%. The CRC may be employed to lower theprobability of false alarm at a base station (e.g., an eNodeB) andtherefore the performance target on Pr(DTX→ACK) (i.e., the probabilitythat the UE has not transmitted any feedback on PUCCH but the basestation detects ACK at the receiver) may be relaxed. The CRC may also beused to indicate the actual payload size used by the UE prior toencoding and/or the identity or number of the configured or activatedserving cells on which the UE receives the DL assignment. The describedCRC embodiment may improve the performance of a detector in case the UEmisses detecting the downlink assignment from the base station on one ormultiple serving cells.

A non-limiting exemplary PUCCH encoding process 2100 for a DFT-S-OFDMbased PUCCH transmission according to an embodiment is illustrated inFIG. 21. At block 2110, UCI data to be fed back by the UE may bereceived, in an embodiment at a coding unit. At block 2120, the entireblock of UCI data may be used to calculate CRC parity bits. The UE atblock 2120 may also append the calculated CRC bits to the UCI bits. Atblock 2130, the CRC bit sequence may be masked by the identity or numberof activated or configured serving cells on which the UE receives DLassignment. At block 2140, the UE may apply a rate 1/3 tail-bitingconvolutional coding on the bits generated at block 2130. At block 2150,rate matching may be performed on the encoded bits.

In an embodiment, in order to maximize the achievable frequencydiversity gain, a UE may employ a channel interleaver for UCItransmissions. Such channel interleaving may be done at the bit leveleither on the encoded bit sequence or on the scrambled bit sequence suchthat bits are written to a rectangular matrix row-by-row and read outcolumn-by-column (e.g., a 24 by 2 matrix for SF=5 and a 48 by 2 matrixfor SF=3.) This matrix may assist in ensuring that adjacent control bitsare being mapped across the two slots. Channel interleaving as disclosedherein may also be applied on the symbol level. In such an embodiment,adjacent UCI modulated symbols may be mapped first in the time domainacross the two slots within a subframe, and then in the frequency-domainacross the subcarriers within each slot. For example, even QPSK symbolsmay be transmitted on the even slots and odd QPSK symbols mapped on thesecond slot.

In such an embodiment, symbols (or coded bits) may be multiplexed intothe PUCCH resource from CSI (i.e., CQI, RI and/or PMI information) andHARQ ACK/NACK information when separate coding and interleaving isapplied on these different types of information. In order to achieve abetter channel coding gain, dimensioning of the corresponding resourceswith respect to the ACK/NACK and/or CSI payload may be applied within asingle RB.

In such an embodiment, where only HARQ acknowledgements are transmitted,the available resources on the PUCCH may be used for ACK/NACK/DTXfeedback transmissions. The mapping rule may be that the HARQ ACK/NACKsymbols are first mapped in the time-domain across the two slots andthen across the frequency-domain across the subcarriers. Alternatively,the symbols may be first mapped in the frequency domain and then mappedin the time domain.

In an embodiment, where only channel status reports are transmitted, theavailable resources on the PUCCH may be used for CSI feedbacktransmissions. The mapping rule may be such that the channel statusreport symbols are first mapped in the time-domain across the two slotsand then across the frequency-domain across the subcarriers.Alternatively, the symbols may be first mapped in the frequency domainand then mapped in the time domain.

In yet another such embodiment, where HARQ feedback and CSI aremultiplexed, different control signaling may be allocated a differentsize of physical resource elements. The size of the reserved resourcesused for each of ACK/NACK and CSI may be scaled according to thevariable coding rate and the modulation order to be used for a givencontrol signaling. Accordingly, a UE may use different offsets for themapping of various controls signaling information where the offsets aresemi-statically configured by higher-layer signaling. Controlinformation may be mapped in such a way that each of ACK/NACK and CSI ispresent in both slots of the subframe.

In embodiments where HARQ ACK/NACK feedback and CSI are multiplexed intothe same PUCCH resource, various means and methods maybe used todetermine the respective number of symbols used for each type ofinformation. In an embodiment, HARQ ACK/NACK information may beprioritized over CSI information. In this embodiment, the number ofcoded symbols required for HARQ ACK/NACK information, Q_(AN) _(_)_(PUCCH), may be determined. If Q_(AN) _(_) _(PUCCH) is smaller than themaximum number of symbols available in the PUCCH Q_(MAX) _(_) _(PUCCH)(in an embodiment, by a minimum margin), the CSI information may bemultiplexed. Otherwise, no multiplexing of HARQ ACK/NACK information andCSI may be performed and only HARQ ACK/NACK information may betransmitted.

The mapping between Q_(AN) _(_) _(PUCCH) and O_(AN) _(_) _(PUCCH)(O_(AN) _(_) _(PUCCH) may be the number of HARQ information bits to betransmitted) may be fixed and provided in a lookup table. Alternatively,Q_(AN) _(_) _(PUCCH) may be calculated as a function of the number ofHARQ information bits to transmit (O_(AN) _(_) _(PUCCH)), aproportionality factor (B_(PUCCH), a parameter that may be predefined orprovided by a higher layer) multiplying the number of HARQ ACK/NACKinformation bit to transmit (this factor may adjust the fraction of thePUCCH energy available to HARQ ACK/NACK information), and/or the maximumnumber of symbols (Q_(MAX) _(_) _(PUCCH)) available for HARQ ACK/NACKinformation and/or CSI information in a DFT-S-OFDM based PUCCHtransmission. The maximum number of symbols may be different dependingon whether extended or normal prefix is used.

The number of symbols Q_(AN) _(_) _(PUCCH) used for HARQ ACK/NACKinformation may correspond to the minimum value between Q_(MAX) _(_)_(PUCCH) and the quantity Q_(AN) _(_) _(PUCCH)=ƒ(O_(AN) _(_)_(PUCCH)×B_(PUCCH)) where the function ƒ( ) may provide the largestpossible number of symbols for HARQ ACK/NACK information that is smallerthan the argument. Alternatively, the function ƒ( ) may provide thesmallest possible number of symbols for HARQ ACK/NACK information thatis larger than the argument. The function ƒ( ) may ensure that a correctnumber of symbols is allocated, given that the granularity of the numberof symbols that can be used in a PUCCH may be larger than one.

Once the number of symbols used for HARQ ACK/NACK information (i.e.,Q_(AN) _(_) _(PUCCH)) is determined, this number may be compared to themaximum number of symbols Q_(MAX) _(_) _(PUCCH) to determine the numberof symbols available to CSI, Q_(CSI) _(_) _(PUCCH). The number ofsymbols available to CSI information Q_(CSI) _(_) _(PUCCH) may be thedifference between Q_(MAX) _(_) _(PUCCH) and Q_(AN) _(_) _(PUCCH). Theremay be a minimum number of symbols available to CSI information to allowmultiplexing between HARQ ACK/NACK information and CSI. If the minimumnumber of symbols is not available, the CSI information may be dropped.In addition, the type of CSI information (as well as the number of DLcarriers being reported) included in available symbols may also be afunction of the number of available symbols for CSI. For instance, ifQ_(CSI) _(_) _(PUCCH) is lower than a threshold, only rank information(RI) for a single DL carrier may be allowed to be included.

Alternatively, or in addition, the amount of CSI information that may beincluded may be determined by a maximum coding rate for CSI information.Such a maximum coding rate may be dependent on the type of CSI (e.g.,the maximum coding rate in case of RI may be lower than for other typeof CSI given the higher robustness requirement.) For instance, themaximum number of information bits available for CSI (O_(CSI) _(_)_(PUCCH)) may be calculated as the product of a maximum coding rate anda number of available coded bits, rounded down (or up) to the closestinteger or to the closest integer matching a possible number of CSIinformation bits. The ratio K between the number of coded bits and thenumber of symbols may correspond to the number of bits per modulationsymbol divided by the spreading factor SF. The embodiments describedabove for multiplexing HARQ ACK/NACK information with CSI may also beused for the multiplexing of different types of CSI in the samesubframe. For instance, such an embodiment may be used for themultiplexing of RI with CQI/PMI where RI is used in place of HARQACK/NACK.

In an embodiment, the placement of symbols in PUCCH for each type ofinformation to be transmitted may be determined. Non-limiting exemplarycontrol signal mapping 1800 for a DFT-S-OFDM based PUCCH transmissionwith SF=5 according to such an embodiment is illustrated in FIG. 22. Asshown in FIG. 22, CSI resources 2240 may be placed at the beginning ofRB 2210 and mapped sequentially to the two slots on one subcarrier ofslot 0 2220 before continuing on the next subcarrier until all resourcesallocated for CSI transmission are filled. HARQ ACK/NACK symbols 2250,on the other hand, may be placed at the end of RB 2210. In other words,CSI 2240 may be frequency multiplexed with HARQ ACK/NACK 2250 on thePUCCH. Reference symbols 2230 may be configured as shown in FIG. 22.

According to another embodiment, the CSI transmitted on PUCCH may usethe same modulation scheme as the HARQ acknowledgements. Alternatively,CSI and HARQ control signaling may be done using different modulationschemes. For example, HARQ ACK/NACK may be modulated using QPSKmodulation, but CSI may be modulated using higher order modulations suchas QAM16 or QAM64.

Various multiplexing methods may be used. The HARQ ACK/NACK symbols maybe placed at both frequency extremities of the RB. This may be donewithin each slot, or alternatively the symbols may be placed at oneextremity for the first slot and at the other extremity for the secondslot. Such an arrangement may maximize frequency diversity for the HARQACK/NACK symbols. Alternatively, or in addition, this arrangement may beused for CSI symbols. In another embodiment, the subcarriers where HARQACK/NACK symbols are placed may be positioned at equal frequencydistance from each other. Alternatively, or in addition, the subcarrierswhere CSI symbols are placed may be positioned at equal frequencydistance.

When CSI information is multiplexed with HARQ ACK/NACK informationaccording to a disclosed embodiment, the encoding of the CSI informationmay be performed using one of several methods. In an embodiment usingpuncturing, CSI information may first be encoded assuming a number ofcoded bits corresponding to the maximum number of symbols AVAILABLE FORHARQ ACK/NACK INFORMATION AND CSI, Q_(MAX) _(_) _(PUCCH). FOR INSTANCE,THE ENCODING may be using a Reed-Muller code RM(K×Q_(MAX) _(_) _(PUCCH),O_(CSI) _(_) _(PUCCH)) where K may be the ratio between the number ofcoded bits and the number of symbols. The CSI coded bits may then beinterleaved, modulated, spread, and positioned in all available symbollocations in the PUCCH. The HARQ ACK/NACK information may also beencoded, interleaved, modulated, spread, and then positioned into asubset of the symbol locations previously utilized by CSI information,in effect puncturing the coding of the CSI. The subset of symbols usedmay be determined according to one of the embodiments of the previoussection.

In another embodiment, CSI information may be directly encoded assuminga number of coded bits corresponding to the number of symbols availableto CSI (Q_(CSI) _(_) _(PUCCH)). For instance, the encoding might beusing a Reed-Muller code RM(K×Q_(CSI) _(_) _(PUCCH), O_(CSI) _(_)_(PUCCH)) where K may be the ratio between the number of coded bits andthe number of symbols. The CSI coded bits may then be interleaved,modulated, spread, and positioned in symbol locations identified for CSIinformation. The HARQ ACK/NACK information may also be encoded,interleaved, modulated, spread, and then positioned into symbollocations not utilized by CSI information. The symbol locations for HARQACK/NACK information and CSI may be determined according to anembodiment described herein. In addition, the transmission of CSI may beprioritized on the codeword with the highest quality metric, for exampleSINR.

Using these embodiments, multiple UEs may be scheduled to share the sameRB for their UL feedback transmissions. Sharing the PUCCH resourceblocks for both HARQ ACK/NACK and CSI transmissions may lead to lowercontrol signaling overhead in the system.

In an embodiment, a UE may be configured to transmit both PUCCH and SRSin the same subframe. In such embodiments, a UE may be configured to nottransmit SRS whenever SRS and a PUCCH format (in an embodiment, based onthe DFT-S-OFDM or similar embodiment described herein) happen tocoincide in the same subframe. In this embodiment, the PUCCHtransmission may take precedence over the SRS transmission.

In another embodiment, a UE may be configured through a higher-layereither to transmit or drop SRS in case of collision between SRS and aPUCCH format (e.g., a new format, such as PUCCH format 3) in a samesubframe. In this embodiment, if the parameter Simultaneous-AN-and-SRSprovided by higher-layers is False, then the UE may not transmit SRS andonly PUCCH may be transmitted in that subframe. However, if theparameter Simultaneous-AN-and-SRS provided by higher-layers is True, theUE may use a shortened PUCCH format in such subframes for transmittingboth feedback and SRS. This new shortened PUCCH format could be used ina cell specific SRS subframe even if the UE does not transmit SRS inthat subframe.

In a shortened PUCCH format, the feedback information may not betransmitted in the last symbol in the second slot of the subframe. As aresult, the spreading factor applied by the UE to the time-domain blockspreading in the second slot may decrease by one compared to that of thefirst slot. Therefore, in the case of DFT-S-OFDM with SF=5, the UE mayuse the length-4 Walsh-Hadmard codes in Table 22 shown below rather thanthe length-5 DFT basis spreading codes in the second slot. Note that inthis case up to four UEs may simultaneously be multiplexed on the sameRB. FIG. 23 illustrates non-limiting exemplary shortened PUCCH structure2300 for a DFT-S-OFDM based PUCCH transmission with SF=5 according tothis embodiment.

TABLE 22 Block spreading sequence indices for second slot using SRStransmission and SF = 5 Orthogonal block Walsh-Hadamard code spreadingcode index of Length-4 0 [+1 +1 +1 +1] 1 [+1 −1 +1 −1] 2 [+1 −1 −1 +1] 3[+1 +1 −1 −1]

In such an embodiment, the UE may determine the index of the blockorthogonal code applied on the data for both of the two slots within asubframe according to:n _(oc,0) =n _(oc,1) =n _(PUCCH) ⁽³⁾ mod N _(SF,0) ^(PUCCH)where n_(oc,0) and n_(oc,1) are the indexes of the block spreading codesfor slots 0 and 1, respectively, and N_(SF,0) ^(PUCCH) is the length ofthe spreading code used for the first slot within a subframe (i.e., slot0.) For example for a DFT-S-OFDM based PUCCH transmission with SF=5, wehave N_(SF,0) ^(PUCCH)=5. Noting that in this case, the base station(e.g., an eNodeB) may make sure that for SRS subframes it only assignsthe n_(PUCCH) ⁽³⁾ values that satisfy the following criterion in orderto avoid any collision among the UEs:n _(PUCCH) ⁽³⁾ mod N _(SF,0) ^(PUCCH)≠4

In an embodiment, a base station may multiplex up to four UEs on theconfigured SRS subframes to transmit their feedback on shortened PUCCHformat 3 and on the same RB. In this case, the UE may identify theorthogonal sequence index applied on the data for both of the two slotswithin a subframe according to:n _(oc,0) =n _(oc,1)=(n _(PUCCH) ⁽³⁾ mod N _(SF,0) ^(PUCCH)) mod N_(SF,1) ^(PUCCH)Moreover, in such an embodiment, the UE may derive the cyclic shift forreference signals (i.e., DMRS), on the pth transmit antennaα_(p)(n_(s),l) for PUCCH format 3 according to:α_(p)(n _(s) ,l)=2π·n _(cs) ^((p))(n _(s) ,l)/N _(sc) ^(RB)wheren _(cs) ^((p))(n _(s) ,l)=(n _(cs) ^(cell)(n _(s) ,l)+n′ _(p)(n_(s))Δ_(shift) ^(PUCCH))mod N _(sc) ^(RB)with n_(cs) ^((p))(n_(s),l) as a cell-specific parameter that varieswith the symbol number l and the slot number n_(s) and

${n_{p}^{\prime}\left( n_{s} \right)} = \left\{ {{\begin{matrix}{n^{\prime}\left( n_{s} \right)} & {{{if}\mspace{14mu} p} = 0} \\{\left( {{n^{\prime}\left( n_{s} \right)} + p} \right){mod}\mspace{11mu} N_{{SF},0}^{PUCCH}} & {otherwise}\end{matrix}\mspace{14mu}{and}{n^{\prime}\left( n_{s} \right)}} = {n_{PUCCH}^{(3)}{mod}\mspace{11mu} N_{{SF},0}^{PUCCH}}} \right.$for n_(s) mod 2=0 and byn′(n _(s))=└N _(SF,0) ^(PUCCH)(n′(n _(s)−1)+1┘ mod(N _(SF,0)^(PUCCH)+1)−1for n_(s) mod 2=1.

In an embodiment using DFT-S-OFDM with SF=3, a UE may use a combinationof the length-3 DFT basis spreading codes and the length-2 Walsh-Hadmardcodes shown below in Table 23 rather than the length-3 DFT basisspreading codes for the second slot. Note that in this embodiment, up totwo UEs may simultaneously be multiplexed on the same RB. FIG. 24illustrates non-limiting exemplary shortened PUCCH structure 2400 for aDFT-S-OFDM based, or similar, PUCCH transmission with SF=3 according tothis embodiment.

TABLE 23 Block spreading sequence indices for the second half of thesecond slot in the case of SRS with SF = 3 Orthogonal blockWalsh-Hadamard code spreading code index of Length-2 0 [+1 +1] 1 [+1 −1]

In an embodiment where extended cyclic prefix (CP) transmission is used,control feedback information (e.g., HARQ ACK/NACK and/or CSI) may beblock spread and transmitted on the five data SC-FDMA symbols availablein each slot. FIG. 25 and FIG. 26 illustrate non-limiting feedbacktransmission structures for extended CP according to this embodiment fora DFT-S-OFDM based or similar structure with SF=5 (e.g., structure 2500of FIG. 25) and SF=3 (e.g., structure 2600 of FIG. 26.) Morespecifically, in the case of extended CP, five SC-FDMA symbols (i.e.,0th, 1th, 2th, 4th, 5th symbols) may be used for ACK/NACK transmissionand one RS symbol, which is the 3rd SC-FDMA symbol index within eachslot, may be used for DM-RS transmission. Note that in the case of SF=5,a UE may use the length-5 DFT basis spreading codes (as the one used fornormal CP) for block spreading of the UCI on the data SC-FDMA symbols,while in the case of SF=3, the UE may use a combination of the length-3DFT basis spreading codes and the length-2 Walsh-Hadmard codes in Table23 above for block spreading in both slots. Also note that in the caseof extended CP, the UE multiplexing capacity of the DFT-S-OFDM basedstructure with SF=3 may be reduced by one compared to that of normal CP.There may be no time-domain orthogonal cover code on the MDRS symbols.

In embodiments where the transmission of both UCI and SRS are configuredin the same subframe with extended CP, a similar approach as the onedescribed previously for normal CP may be employed for SF=5. In the caseof SF=3, the shortened PUCCH format may apply the length-3 DFT basisspreading codes for the first half of the second slot and no spreadingcode may be used for the single SC-FDMA symbol in the right hand side ofthe DM-RS symbol.

In an embodiment, methods for the transmission of information bits(e.g., HARQ ACK/NACK information bits) based on Channel Selection may beused. At least one bit may be more robustly conveyed by the selection(at the transmitter) and the detection (at the receiver) of the index orindices on which a transmission is performed. Such embodiments may takeinto consideration the robustness properties of the Channel Selectiontransmission method, for example when applied to transmission(s) of UCIinformation on PUCCH.

In an embodiment, information bit(s) of higher priority may be mapped tothe bit(s) with a more robust encoding. For example, in the case ofchannel selection, the mapping is made to one or more bit(s) that areimplicitly encoded from the presence/absence of a signal in a specifictransmission resource(s). Such information bits may be HARQ ACK/NACKinformation bits corresponding to a downlink transmission (e.g., a DCIformat or a PDSCH transmission) and may be transmitted using multiplePUCCH indices (or resources) corresponding to PUCCH using, for example,format 1a/b. Additionally, such information bits may also be informationbit(s) corresponding to another type of UCI that may be multiplexed withthe HARQ ACK/NACK feedback such as an SR. The relative priority ofinformation bits may be derived based on at least one of whether theinformation bit(s) corresponds to a transmission in a given downlink CC(for example, a bit may be given higher priority if it corresponds to atransmission in a PCell, or a bit may be given higher priority if itcorresponds to a transmission in a serving cell associated to a UL CCwhich may carry UCI on PUSCH and/or PUCCH), the relative priority of theinformation bit(s) may provided by the relative priorities for uplinklogical channel prioritization of the UL CCs associated with thecorresponding serving cells, and the relative priority may be derivedfrom the explicit semi-static configuration by RRC of priority orderand/or the implicit semi-static configuration of the SCells.

In any of these embodiments, the transmission may be a transmission of aDCI message on PDCCH (including, for example, a (de)activationindication for a configured UL grant and/or DL assignment (SPS), a(de)activation indication for SCell, and/or a downlink assignment), atransmission on PDSCH, or a transmission on a multicast channel. Forsuch transmissions, a DCI message on PDCCH for SPS or SCell(de)activation and/or a transmission on PDSCH may be given highestpriority.

In an embodiment, the information bits that are mapped to the bit(s)with a more robust encoding may be changed from subframe to subframe, insuch a way that the reliability of different types of information isequal in average over time. For instance, the order of HARQ ACK/NACKinformation bits prior to mapping to the channel selection scheme may beb0, b1, b2, . . . , bn, where bm might correspond to the HARQ ACK/NACKinformation pertaining to a transmission on the mth DL carrier (otherinterpretations are also contemplated.) To avoid the situation where thereliability of b0, b1, b2, bn is systematically higher than other bits,the information bits b0, b1, b2, . . . , bn may be reordered (orscrambled) prior to mapping to the channel selection scheme according toa known rule (i.e., a rule known to both the transmitter and thereceiver), in such a way that the order may be different in successivesubframes. The order may be a function of the system frame number,subframe number, or a combination thereof. It may also be a function ofother parameters such as the physical cell identity. The scramblingfunction may be known at both the UE and the network.

In an embodiment, a UE may be configured to multiplex UCI for PUCCH (inan embodiment using PUCCH format 2) to carry SR and HARQ ACK/NACK andutilizing PUSCH (format without data), to carry CSI (e.g., CQI, PMI,RI.) In some such embodiments, for example where a UE may be operatingin an LTE-A environment, the UE may be configured to use PUCCH only forLTE compatible case (e.g., where only one CC assigned.) In suchembodiments, the UE may use PUCCH format 2 to carry SR and HARQ ACK/NACKto support the bandwidth extension (multi carriers) in LTE-A systems.The HARQ ACK/NACKs in LTE-A may replace CQI/PMI/RI as used in LTE R8. Inaddition, the SR may be formatted and sent using any of severalembodiments.

In an embodiment, an SR may be superimposed on the reference signals,for example, as may be done with HARQ ACK/NACK in LTE-R8. For instance,if an SR is positive, the reference signals on the 5th and 12th OFDMsymbols may be multiplied by −1. Illustrated in FIG. 27 is non-limitingexemplary PUCCH structure 2700 for a DFT-S-OFDM based PUCCH transmissionwith SF=5 that may be used in such an embodiment. This embodiment may beespecially effective in low Doppler scenarios, and may not be effectivewhen using the extended cyclic prefix mode since there is only a singlereference symbol per slot.

In an embodiment, an example of which is shown in FIG. 27, at the UE theHARQ ACK/NACK information may first be channel coded (in variousembodiments, using Reed-Muller or convolutional code) with input bitsequence a′₀, a′₁, a′₂, a′₃, . . . , a′_(A′-1) and output bit sequenceb′₀, b′₁, b′₂, b′₃, . . . , b′_(B′-1), where B′=20 for PUCCH format 2 orB′=48 for DFT-S-OFDM based PUCCH structure. The scheduling request bitmay be denoted by a″₀. Each positive SR may be encoded as a binary ‘0’and each negative SR may be encoded as a binary ‘1’. Alternatively, eachpositive SR may be encoded as a binary ‘1’ and each negative SR may beencoded as a binary ‘0’. In such embodiments, the output of the channelcoding block may be given by b₀, b₁, b₂, b₃, . . . , b_(B-1), whereb_(i)=b′_(i), i=0, . . . , B′−1 and b_(B′)=a″₀ with B=(B′+1).

The block of encoded bits may be interleaved, scrambled with aUE-specific scrambling sequence, and modulated resulting in a block ofcomplex-valued modulation symbols d(0), . . . ,

$d\left( \left\lfloor \frac{B}{2} \right\rfloor \right)$for the ACK/NACK payload. A single BPSK modulation symbol

$d\left( {\left\lfloor \frac{B}{2} \right\rfloor + 1} \right)$carrying an SR information bit may be used in the generation of one ofthe reference-signals for PUCCH format 2 or DFT-S-OFDM based PUCCHstructure.

In an embodiment, one of the reference symbols may be modulated with analternative cyclic shift. In a non-limiting example, a UE may beconfigured with a pair of orthogonal sequences, where the two sequencesare implicitly determined from the same Control Channel Element (CCE) ofthe PDCCH. There may be a one-to-one mapping between one of the assignedsequences and the positive SR and a one-to-one mapping between the otherassigned sequence and the negative SR. In such an embodiment, the UE mayfirst determine the resources for concurrent transmission of HARQ-ACKand SR on PUCCH by a resource index (e.g., n_(PUCCH) ⁽¹⁾). The UE maythen determine the pair of cyclic shifts (e.g., α₁, α₂) based on theassigned resource.

In an embodiment, a UE may jointly code an SR bit with HARQ ACK/NACK ata known bit position (e.g., the first or last bit) prior totransmission, as illustrated in FIG. 28 that shows non-limitingexemplary PUCCH structure 2800. In this embodiment, at the UE, theuncoded HARQ-ACK information denoted by a′₀, a′₁, a′₂, a′₃, . . . ,a′_(A′-1) may be multiplexed with the Scheduling Request (SR) bit toyield the sequence a₀, a₁, a₂, a₃, . . . , a_(A-1), where a_(i)=a′_(i),i=0, . . . , A′−1 and a_(A′)=a″₀ with A=(A′+1). The sequence a₀, a₁, a₂,a₃, . . . , a_(A-1) may be channel encoded using a Reed-Muller orconvolutional code to yield the output bit sequence b₀, b₁, b₂, b₃, . .. , b_(B-1) where B=20 for PUCCH format 2 or B=48 for DFT-S-OFDM basedPUCCH structure. This embodiment may be especially effective in highDoppler scenarios, and may be used when using the extended cyclic prefixmode despite there being only a single reference symbol per slot.

In an embodiment, where joint coding using the Reed-Muller code is usedand the codewords may be a linear combination of the A basis sequencesdenoted by M_(i,n), the SR bit may be spread by the most reliable basissequence that could maximize the frequency diversity gain. For example,the basis sequence candidate that could potentially disperse the SRinformation coded bit more evenly across the subframe may be the oneselected for encoding of the SR bit. In this embodiment, the encoded bitsequence of length B at the output of the channel encoder may be givenby:

$b_{i} = {{a_{m} \cdot M_{i,m}} + {\sum\limits_{{n = 0},{n \neq m}}^{A - 1}{a_{n} \cdot M_{i,n}}}}$i = 0, 1, …  , B − 1,A non-limiting exemplary basis sequence for RM(20, k) for encoding theSR information bit is shown below in Table 24.

TABLE 24 Example basis sequence for RM(20, k) for encoding the SRinformation bit i M_(i, 0) M_(i, 1) M_(i, 2) M_(i, 3) M_(i, 4) M_(i, 5)M_(i, 6) M_(i, 7) M_(i, 8) M_(i, 9) M_(i, 10) M_(i, 11) M_(i, 12) 0 1 10 0 0 0 0 0 0 0 1 1 0 1 1 1 1 0 0 0 0 0 0 1 1 1 0 2 1 0 0 1 0 0 1 0 1 11 1 1 3 1 0 1 1 0 0 0 0 1 0 1 1 1 4 1 1 1 1 0 0 0 1 0 0 1 1 1 5 1 1 0 01 0 1 1 1 0 1 1 1 6 1 0 1 0 1 0 1 0 1 1 1 1 1 7 1 0 0 1 1 0 0 1 1 0 1 11 8 1 1 0 1 1 0 0 1 0 1 1 1 1 9 1 0 1 1 1 0 1 0 0 1 1 1 1 10 1 0 1 0 0 11 1 0 1 1 1 1 11 1 1 1 0 0 1 1 0 1 0 1 1 1 12 1 0 0 1 0 1 0 1 1 1 1 1 113 1 1 0 1 0 1 0 1 0 1 1 1 1 14 1 0 0 0 1 1 0 1 0 0 1 0 1 15 1 1 0 0 1 11 1 0 1 1 0 1 16 1 1 1 0 1 1 1 0 0 1 0 1 1 17 1 0 0 1 1 1 0 0 1 0 0 1 118 1 1 0 1 1 1 1 1 0 0 0 0 0 19 1 0 0 0 0 1 1 0 0 0 0 0 0

In an embodiment, where a new PUCCH structure may be used (e.g., ifintroduced in LTE-A R10) for multiple ACK/NACK transmissions that isbased on a PUCCH format 1 structure, a UE may transmit the ACK/NACKresponses on its assigned ACK/NACK PUCCH resource for a negative SRtransmission and on its assigned SR PUCCH resource for a positive SR. Inthis embodiment the PUCCH format used may be a new PUCCH format.

In an embodiment, SR bits may puncture the encoded HARQ ACK/NACKsequence. In such an embodiment, at the UE, the HARQ ACK/NACKinformation may be channel coded using a Reed-Muller or convolutionalcode with input bit sequence a′₀, a′₁, a′₂, a′₃, . . . , a′_(A′-1) andoutput bit sequence b′₀, b′₁, b′₂, b′₃, . . . , b_(B′-1), where B′=20for PUCCH format 2 or B′=48 for DFT-S-OFDM based PUCCH structure. Thescheduling request bit may be denoted by a″₀. The output of this channelcoding block may be denoted by b₀, b₁, b₂, b₃, . . . ,b_(B′-1), whereb_(i)=b′_(i), i=0, . . . , B′−1,& i≠j and b_(j)=a″₀. Note that j may bethe index of the bit at the output of the channel coding block that isoverwritten by the SR bit. In an embodiment, the puncturing may beperformed at the symbol-level such that the BPSK modulated SR symbolpunctures one of the QPSK modulated ACK/NACK symbols.

In these embodiments, CSI may be transmitted in a variety of ways. In anembodiment, if there is no collision between HARQ ACK/NACK and CSI for asubframe, CSI may be transmitted on PUSCH without data (PUSCH with onlyCSI), but if there is a collision between HARQ ACK/NACK and CSI for asubframe, only HARQ ACK/NACK will be transmitted for this subframe(i.e., no CSI will be transmitted.) Alternatively, both HARQ ACK/NACKand CSI may be transmitted on PUSCH as described herein. In anembodiment, HARQ ACK/NACK on PUCCH format 2 and CSI on PUSCH withoutdata may be transmitted simultaneously.

In an embodiment where there occurs a collision between ACK/NACK andpositive SR in a same subframe, a UE may be configured to drop ACK/NACKand transmit SR. In this embodiment, the parameterSimultaneousAckNackAndSR provided by higher layers may determine if a UEis configured to support the concurrent transmission of ACK/NACK and SR.In this case, an RRC IE (e.g., SchedulingRequestConfig-R10) may bedefined to enable signaling the parameter SimultaneousAckNackAndSR. Anon-limiting example of such an ID is provided below:

-- ASN1START SchedulingRequestConfig-Rel10 ::= CHOICE { release NULL,setup SEQUENCE { sr-PUCCH-ResourceIndex INTEGER (0..2047),sr-ConfigIndex INTEGER (0..155), dsr-TransMax ENUMERATED { n4, n8, n16,n32, n64, spare3, spare2, spare1} simultaneousAckNackAndSR BOOLEAN } }-- ASN1STOP

In an embodiment, a UE may drop ACK/NACK whenever the HARQ ACK/NACKpayload size exceeds a predetermined value. In this embodiment, the HARQACK/NACK payload size may be a function of configured component carriersand transmission modes. Thus, UE may implicitly know when to dropACK/NACK information once it is configured by a higher layer regardingthe number of CCs and transmission mode on each CC.

In an embodiment, a UE may be configured to determine the transmit powerto be used for a PUCCH transmission. A UE may be configured to controlthe transmit power for a PUCCH transmission of ACK/NACK by defining thetransmit power as a function of at least one of the payload (i.e., theformat) of the PUCCH transmission (for example, the number ACK/NACK bitsto carry inside said payload and/or the ACK/NACK format used to carrysaid payload), the number of codewords per serving cell of the UE'sconfiguration, the number of codewords per active serving cell of theUE's configuration (in an embodiment only those serving cells that wereactivated by FAC), the number of serving cells in the UE'sconfiguration, and the number of active serving cells of the UE'sconfiguration, in an embodiment only those serving cells that wereactivated by FAC.

In an embodiment, given the definition of a PUCCH format supportingjoint coding of the HARQ ACK/NACKs feedback corresponding to a pluralityof (in an embodiment, explicitly activated) serving cells of the UEconfiguration, a power control unit at a UE can adjust for thetransmission power used for the PUCCH format using joint coding as afunction of the HARQ ACK/NACK payload to maintain the UL control channelcoverage to a close approximation of the PUCCH format 1a coverage, forexample in order to make the coverage independent from the number ofconfigured (and possibly explicitly activated) serving cells.

This may be accomplished by defining for transmission of said PUCCHformat using joint coding as follows:

${h\left( {n_{CQI},n_{HARQ}} \right)} = \left\{ \begin{matrix}{10{\log_{10}\left( \frac{n_{HARQ}}{3} \right)}} & {{{if}\mspace{14mu} n_{HARQ}} \geq 3} \\0 & {otherwise}\end{matrix} \right.$The value ‘3’ in the above formula may be based on the fact that theminimum number of HARQ ACK/NACK bits for joint coding in the PUCCHformat using joint coding is expected to be three bits. Alternatively,this value may be replaced by a more generalized parameter n_(HARQ,min)which may denote the minimum number of HARQ ACK/NACK bits to be codedand mapped to the PUCCH format using joint coding. Note that the maximumnumber of HARQ ACK/NACK bits does not impact the above formula.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

What is claimed is:
 1. A channel coding method in a user equipment (UE)comprising: generating a set of bits associated with feedbackinformation, wherein the feedback information comprises one or moreacknowledgement/negative acknowledgement (ACK/NACK) bits; on a conditionthat transmission of the feedback information coincides withtransmission of a scheduling request (SR), appending an SR bit to theset of bits associated with the feedback information; jointly encodingthe set of bits associated with the feedback information and theappended SR bit into jointly encoded control information bits;scrambling the jointly encoded control information bits to generatescrambled control information bits; modulating the scrambled controlinformation bits to generate modulated symbols; determining anorthogonal sequence index; spreading the modulated symbols block-wiseusing at least one orthogonal sequence indicated by the orthogonalsequence index; and transmitting the block-wise spread modulated symbolsassociated with the jointly encoded control information bits on aphysical uplink control channel (PUCCH).
 2. The method of claim 1,wherein the orthogonal sequence index is determined based on a radioresource control (RRC) message.
 3. The method of claim 2, wherein one ofthe at least one orthogonal sequence is associated with a configuredcode length.
 4. The method of claim 3, wherein the at least oneorthogonal sequence comprises a first orthogonal sequence and a secondorthogonal sequence, wherein the first orthogonal sequence is applied toa first set of symbols and the second orthogonal sequence is applied toa second set of symbols.
 5. The method of claim 4, wherein the secondorthogonal sequence is determined based on a second orthogonal sequenceindex.
 6. The method of claim 1, wherein the at least one orthogonalsequence is used to spread at least a portion of the modulated symbolsover a set of orthogonal frequency division multiplexing (OFDM) symbols.7. The method of claim 1, wherein a positive SR is encoded as a binary 1and a negative SR is encoded as a binary
 0. 8. The method of claim 1,wherein the bits associated with the feedback information and theappended SR bit are jointly encoded using a Reed-Muller code.
 9. Themethod of claim 1, comprising applying a circular repetition on thejointly encoded control information bits.
 10. The method of claim 1,wherein the block-wise spread modulated symbols are transmitted using adiscrete Fourier Transform-spread-orthogonal frequency divisionmultiplexing (OFDM) (DFT-s-OFDM) based PUCCH structure.
 11. The methodof claim 1, wherein the one or more acknowledgement/negativeacknowledgement (ACK/NACK) bits are associated with a plurality ofcomponent carriers.
 12. A user equipment (UE) comprising: a processorconfigured to at least: generate a set of bits associated with feedbackinformation, wherein the feedback information comprises one or moreacknowledgement/negative acknowledgement (ACK/NACK) bits; on a conditionthat transmission of the feedback information coincides withtransmission of a scheduling request (SR), appending an SR bit to theset of bits associated with the feedback information; jointly encode theset of bits associated with the feedback information and the appended SRbit into jointly encoded control information bits; scramble the jointlyencoded control information bits to generate scrambled controlinformation bits; modulate the scrambled control information bits togenerate modulated symbols; determining an orthogonal sequence index;spread the modulated symbols block-wise using at least one orthogonalsequence indicated by the orthogonal sequence index; and transmit theblock-wise spread modulated symbols associated with the jointly encodedcontrol information bits on a physical uplink control channel (PUCCH).13. The UE of claim 12, wherein the orthogonal sequence index isdetermined based on a radio resource control (RRC) message.
 14. The UEof claim 13, wherein one of the at least one orthogonal sequence isassociated with a configured code.
 15. The UE of claim 14, wherein theat least one orthogonal sequence comprises a first orthogonal sequenceand a second orthogonal sequence, wherein the first orthogonal sequenceis applied to a first set of symbols and the second orthogonal sequenceis applied to a second set of symbols.
 16. The UE of claim 15, whereinthe second orthogonal sequence is determined based on a secondorthogonal sequence index.
 17. The UE of claim 12, wherein the at leastone orthogonal sequence is used to spread at least a portion of themodulated symbols over a set of orthogonal frequency divisionmultiplexing (OFDM) symbols.
 18. The UE of claim 12 wherein a positiveSR is encoded as a binary 1 and a negative SR is encoded as a binary 0.19. The UE of claim 12, wherein the bits associated with the feedbackinformation and the appended SR bit are jointly encoded using aReed-Muller code.
 20. The UE of claim 12, wherein the processor isconfigured to apply a circular repetition on the jointly encoded controlinformation bits.
 21. The UE of claim 12, wherein the block-wise spreadmodulated symbols are transmitted using a discrete FourierTransform-spread-orthogonal frequency division multiplexing (OFDM)(DFT-s-OFDM) based PUCCH structure.
 22. The UE of claim 12, wherein theone or more acknowledgement/negative acknowledgement (ACK/NACK) bits areassociated with a plurality of component carriers.